All tiers of Sniper Rifle can be equipped with an additional Weapon Attachment.
Oh, and if you hadn't guessed from my framing, the Darklance doesn't benefit from Modular Sniper Rifles. By a similar token, the Tactical Legacy Pack weapons don't benefit from their respective Modular Breakthroughs, meaning Modular Breakthroughs will make their matching TLP weapon type something you'll ideally try to replace.
Modular Shotguns
All tiers of Shotgun can be equipped with an additional Weapon Attachment.
Like Modular Sniper Rifles, this takes the Conventional tier to 2 slots, and the later tiers to 3 slots. Also like Modular Sniper Rifles, in the long haul you probably don't care; the Arashi is better, and doesn't benefit.
So, just like Modular Sniper Rifles, I'm willing to burn a Covert Op on it, but not lab time.
Modular Cannons
All tiers of Cannon can be equipped with an additional Weapon Attachment.
This is by far the best of the Modular Breakthroughs that isn't for a Resistance class weapon, since there's no Chosen weapon to render it close to irrelevant in the long haul. Grenadiers can get by pretty well on just two Weapon Attachments, but having three will particularly help shooting-focused Grenadiers do their job reliably and effectively.
I personally am usually reluctant to burn lab time on it, in part because honestly Grenadiers are the class I'm most prone to leaving behind on the Avenger in War of the Chosen, to the point that I've had multiple runs where no Grenadier ever reached Colonel, and indeed in a couple of runs my highest-level Grenadier at the end of the game was only a Captain. If you're more prone to using Grenadiers than I, though, feel free to burn lab time on it; it's an investment that won't be displaced down the line.
As an aside, SPARKs don't have a Modular Breakthrough, and don't benefit from existing ones. There's a mod that addresses this by making both Cannon breakthroughs affect SPARK cannons; that this isn't default behavior is honestly surprising to me, hence part of why I'm covering this here in particular.
Modular Assault Rifles
All tiers of Assault Rifle can be equipped with an additional Weapon Attachment.
This is slightly less prone to being long-haul underwhelming compared to Modular Shotguns and Modular Sniper Rifles simply because three classes can use Rifles and so even if you don't ever double up on a class you may find yourself passing out the Disruptor Rifle, only to find you still need to pass out a regular Plasma Rifle because eg you're fielding a Specialist and Psi Operative simultaneously.
It still gets hurt by acquiring the Disruptor Rifle (Which, as you might have already guessed, doesn't benefit from Modular Assault Rifles), but not quite so dramatically as those two experience with their own Chosen weapons.
I tend to be reluctant to burn lab time on it, personally, but that's in part because I have Alien Hunters and so tend to give a Psi Operative the Bolt Caster. If you don't have Alien Hunters, or do but hate the Bolt Caster (Which is not unreasonable), then you'll want your regular Rifles at their best, and may consider lab time spent on it worthwhile.
It's really too bad War of the Chosen didn't provide Weapon Attachment options for the Bolt Caster...
Modular Bullpups
All tiers of Bullpup can be equipped with an additional Weapon Attachment.
Skirmishers are the class that most desperately wants as many slots on their weapon as possible, since basically only Laser Sights aren't unusually good in their hands, and in particular they honestly basically want both an Expanded Magazine and an Autoloader to minimize shots lost to the need to reload. Having a third slot lets them slap on a Scope to get more reliable at hitting things at a distance, or a Hair Trigger to leverage their ability to roll for it at least twice a turn most turns, or a Repeater for the same reason and to somewhat make up for their poor per-hit damage. Those are all nice possibilities that are lovely to be able to slap in atop All The Ammo You Will Ever Need, Hopefully.
As such, I personally consider this one of the best Modular Breakthroughs, especially since no Chosen weapon will ever displace your regular Bullpups. It does a surprising amount to push Skirmisher from 'above-average, but not stupendously memorable in that regard' to 'actually prone to being MVP'.
Of course, if you're not much of a fan of Skirmishers, or prefer to focus on their abilities not centered on shooting, you can feel free to skip it yourself. It does make Skirmishers a lot better, but it's not like it makes them so good that not using them is criminally stupid.
Just as with Improved Bullpups, Skirmishers can offer this and the other Resistance factions can't. The result that Modular Bullpups is fairly rare to get is actually fairly painful, since they really do want... well, like five Weapon Attachment slots, frankly, but the point is that for Bullpups operating with just two slots is torture. And most runs will be stuck with just the two.
Modular Vektor Rifles
All tiers of Vektor Rifle can be upgraded with an additional Weapon Attachment.
High-level Reapers really want all of a Scope, Expanded Magazine, and either a Repeater (For killing Chosen/Alien Rulers with Banish) or a Hair Trigger. (For general Silent Killer usage) As such, this is fantastic to acquire, and given Reapers are really desirable to have in many of the toughest missions, it's basically a must-have if you're not doing some manner of gimmick run. I'm outright willing to burn lab time on this, in most cases.
Just like Modular Bullpups, this continues the thing of Resistance factions not being able to offer Breakthroughs that benefit other Resistance faction classes. Also like Modular Bullpups, the resulting rarity in ability to get a third slot for Vektor Rifles is actually quite painful, though overall a bit less so than with Bullpups.
Reinforced Light Armor
+1 HP on Spider Suits and Wraith Suits.
This does not affect the Serpentsuit. If you've got all the DLC and like to actually leverage it all, this makes Reinforced Light Armor extremely dubious, even more so than it already is. If you're equipping all three Ruler armors on a consistent basis in the late game -and the Icarus Armor and R.A.G.E Armor are both flat improvements over their regular tier-equivalent counterparts, while the Serpent Armor is generally better than a Wraith Suit, so you should if you have the Alien Hunters DLC- then you already only have half your squad slots wanting to maybe use a Spider Suit/Wraith Suit. And then that gets cut further by any SPARKs/Resistance soldiers you bring along! It's entirely possible to end up fielding a squad that has no room for a Wraith Suit.
But even if you don't have the Alien Rulers and/or Shen's Last Gift DLCs, this is pretty dubious. +1 HP is unlikely to help in any meaningful sense once you have access to second-tier armors, and it only applies to the limited subset of soldiers you specifically equip with light armors in the first place. Not helping is that Rangers and Sharpshooters are overall the best users of light armors; Rangers in the late game will have Untouchable so that even being targeted by guaranteed-damage effects doesn't, you know, guarantee damage, making +1 HP less important, and sniping Sharpshooters love the light armor-derived ability to re-position while still being able to fire their Sniper Rifle... and if you're actually focused on sniping with them, they shouldn't usually be in a position to get shot at in the first place, making +1 HP literally worthless.
If it shows up via Covert Op and either you don't have better Covert Ops available or the Covert Op happens to have a booster you want (eg to promote someone to Captain for Squad Size II), then sure, go ahead and grab it, but if it shows up in the lab you should probably skip it.
Reinforced Heavy Armor
+1 HP on E.X.O. Suits and W.A.R. Suits.
As with Reinforced Light Armor, this doesn't apply to the R.A.G.E. Suit, and so is hurt notably by having the Alien Hunters DLC. Also like Reinforced Light Armor, getting a hit point from a Breakthrough is pretty unlikely to matter anyway.
That said, of the two Reinforced Heavy Armor is more inherently meritful. A Blast Padding soldier in a W.A.R. Suit actually has respectable damage reduction, making it more plausible an additional hit point will actually help, and in general the heavy armors inherently encourage having those soldiers tank hits for people in lighter armors where feasible.
You should still probably skip it if it shows up in the lab, but it's a lot more worth considering when it shows up in Covert Op form, especially if you've got an unusually large number of Salvo soldiers.
Oh, and no, there is no Medium Armor HP-boosting Breakthrough. I'm not sure why. Not enough development time? Or maybe they felt it was too generically good, for reasons like that it would be a continuous boost to Resistance class HP?
On that note, no, SPARKs don't benefit from either armor Breakthrough. Alas. Not that it hurts them much given how underwhelming these particular Breakthroughs are, but still.
Note that the mod I linked to earlier that makes SPARK cannons benefit from Improved and Modular Cannons also makes it so that both this and the light armor Breakthrough benefit the Alien Ruler armors. Still not SPARKs, though.
Really, these needed to be bigger boosts, or provide different benefits. If the light armor Breakthrough was +1 to Mobility, that would be small but worthwhile. If the heavy armor Breakthrough provided a second Heavy Weapon use, that'd be fantastic, or if it provided a point of Armor that would encourage doing stuff like buying Blast Padding on soldiers more regularly and stuffing them into heavy armors. I can kind of see the thought process, in that HP boosting is in some sense the defensive equivalent to damage boosting on weapons, but XCOM 2 is heavily slanted toward 'kill everything so it doesn't get a turn' so HP only helps when you've screwed up, whereas damage helps basically all the time, and furthermore damage boosting helps every single time you land a shot, where HP boosting helps only once, at most, per mission. (Ignoring Medikit healing, admittedly, but you're pretty unlikely to survive by the skin of your teeth multiple times within a single mission)
So +1 HP on armors is really just... not equivalent to +1 damage on weapons. It's much lesser value in actuality.
It does admittedly slightly reduce average wound recovery time, I suppose?...
Adaptive Personal Combat Sims
When replacing a PCS on a soldier, the old PCS is returned to inventory instead of being permanently lost.
This is an okay Breakthrough. Not stupendous or anything, but being able to swap in a Superior PCS on an A-team soldier and then dump their old Basic or Advanced PCS on one of your secondary soldiers is worth something, making your PCS drops go further, and making it so you don't need to think strongly on the long-term aspect of PCS distribution. I basically always grab it if it shows up, but to be honest I would totally understand someone who felt it wasn't worth the bother and skipped it every time.
Note that it's generally somewhat obvious whether you have the Breakthrough or not. If you have it, and have a PCS in storage, then the exclamation point beside the PCS menu button will appear even on soldiers who have PCSes installed, so long as at least one PCS in storage isn't the same kind and an equal or worse bonus as their current PCS. (That is; if they have a Superior Perception PCS worth +13 Aim, and all that's in storage is Perception PCSes that provide +13 or less Aim, the exclamation point won't appear. But even another Superior Perception PCS can make the exclamation point appear, so long as it's providing +14 or more Aim) As you can readily see from that same screen whether the soldier has a PCS currently equipped or not, it's easy to see whether the exclamation point is there because they have nothing equipped or there because you have Adaptive Personal Combat Sims and a not-completely-worse option in storage.
Also note that the game still won't let you directly replace a PCS with a worse version of the same. You can work around this by swapping to a different kind of PCS (eg Superior Conditioning->Agility of some kind->Advanced Conditioning), but that of course requires you have more than one PCS in storage. It's a bit janky, and honestly this probably should've added in functionality to directly uninstall PCSes.
Interchangeable Upgrades
When replacing a Weapon Attachment, the old Weapon Attachment is returned to inventory instead of being permanently lost.
A point of note: strictly speaking the game provides no easy feedback on whether you've got this effect or not, but fortunately it's easy to check for it if you don't remember whether a given run has acquired it or not; simply try to install a Weapon Attachment into a weapon, over an existing Weapon Attachment. If you have it, it will go right in, and you can then swap it right back out; no harm done. If you don't have it, the game will promptly inform you this is a permanent choice that cannot be undone and are you sure you want to do it?
Or I suppose you could go digging in the lab's research archives, but that's honestly going to be slower and less convenient in most cases.
In any event, this is one of those must-have Breakthroughs you should basically always go for unless you're doing some manner of gimmick run that has no use for Weapon Attachments. It effectively is worth some Supplies, since you'll turn around and sell old Weapon Attachments once they've been swapped for superior versions instead of them vanishing into the ether, it gives you the ability to adjust soldier gear on the fly to accommodate specific missions (eg subbing in an Expanded Magazine for Lost missions on someone who normally doesn't need ammo support), and it even, somewhat awkwardly, allows you to shuffle Attachments across classes. It's especially helpful if acquired in the early game, letting you more freely throw in Weapon Attachments on whoever without worrying about the long haul; only got a Laser Sight and want your Skirmisher better? Throw it right on, you can just swap it out later, so the fact that it's really pretty bad for a Skirmisher isn't a reason to keep it uninstalled.
Moderate complaint: this really ought to have let you straight-up strip out Weapon Attachments from a weapon, returning them to the general pool. As-is, you can only remove a Weapon Attachment if you have something to sub in over it, which creates a bizarre incentive to keep at least one Weapon Attachment in storage so you can shuffle Weapon Attachments around. It's particularly frustrating because Long War 2 coded up such functionality, so the concept and code have already been put out there, and there's no way the War of the Chosen development team was unaware of this point, as they actively worked with Pavonis to help make Long War 2 happen. It's not a huge deal or anything, but frustrating and weird.
Spare Parts I
Proving Grounds Projects cost 20% less, where applicable.
It's really too bad Spare Parts I and II are individually so low in value. Since this is so, it's dubious to pursue them individually, and in turn you're unlikely to get both together to thus get the Elerium Core cost reduction that requires both.
Future Combat I
Guerrilla Tactics School upgrades cost 20% less.
If you're playing below Legend, this is liable to be virtually worthless; GTS upgrades are cheap, and even with all the rank requirements you'll often have bought most of them before you were ever offered Future Combat I. Saving 20% of the cost of 150 Supplies worth of upgrades is probably not worth the lab time, nor worth a Covert Op when you could instead perform a Supply Run or something.
Annoyingly, the game is perfectly happy to keep trying to offer it even once you've purchased literally every GTS upgrade, clogging up your Covert Ops or wasting a Breakthrough roll in the lab.
Up in Legend, this actually has the potential to be solid. Your soldiers take longer to reach Captain, so you're more likely to have it arrive before it's too late to help, and the GTS class skill purchases are almost three times as expensive; instead of saving 20% on 150 Supplies worth of upgrades, you're a lot more likely to be saving 20% on 1000 or more Supplies worth of upgrades. 200 Supplies is meaningful!
Future Combat II
Guerrilla Tactics School upgrades cost a further 30% less.
Yes, this is the same graphic as Future Combat I. Yes, that's the way it is in-game.
Like Future Combat I, Future Combat II is almost always worthless below Legend, rarely being offered early enough to have any chance of being a good deal, while up in Legend it has pretty decent odds of being pretty darn good. Saving 300 Supplies because you've got 1000 Supplies of upgrades waiting to be bought is very good.
Also like Future Combat I, the game is perfectly happy to keep trying to offer it even after you've bought all the upgrades, which is frustrating.
Proving Ground Construction
The Proving Ground facility costs half as much to construct.
This is the first example of a series of Breakthroughs relating to facility construction, and unfortunately it's pretty representative of how dubious they are: first of all, several facilities are priority constructions, such that it's unlikely you'll get the Breakthrough before you build them. Second of all, the benefit isn't that significant: 50% off sounds like a lot, but the Proving Ground only costs 100 Supplies in the first place, so this is just saving you 50 Supplies. Even early in the game 50 Supplies really isn't that significant, and critically a Supply Run Covert Op can provide notably more than that. So if you have both a Supply Run and one of these Breakthroughs available via Covert Op simultaneously... the Supply Run is generally going to be the same thing but better. Third of all, the game will only offer such Breakthroughs if you currently have the option of building the structure; in the case of the Proving Ground, you'll need to perform the ADVENT Officer Autopsy to unlock the Proving Ground. This limits the window in which you can be offered these Breakthroughs; if you unlock the Proving Ground and immediately go to build it, the game had one split-second opportunity to offer this Breakthrough; immediately after you finished the Officer Autopsy.
The plus side to this is that the game will always stop trying to offer these Breakthroughs if you've already built the relevant facility and it's a facility capped at 1 copy, such as the Proving Ground, and therefore you don't have to worry about them clogging up Covert Op slots or wasting Breakthrough spawns. Aside the edge case of the month rolling over, then you start building the facility, then your ongoing Covert Op completes and you discover that you got the Breakthrough for the facility you already started building, but, you know, edge case. And if you're really worried about that kind of thing, you can check your Covert Op list when the month rolls over instead of waiting for your current Covert Op to complete.
In theory it's a little more appealing when acquired as a proper lab research topic, since you're turning 'free' lab time into Supplies, a task otherwise impossible, but there's a pretty narrow portion of the game where this is plausibly a good deal. Early in the game, your research really needs to go to actual priorities, like making progress on plot topics and unlocking magnetic weapons and Predator armor. Late in the game, when you have a bit more freedom for assigning researches, Supplies is pretty much always the thing you have more than you know what to do with. There's a brief phase in the early midgame where you may find yourself with nothing better for your research to be focused on and an urgent need for Supplies, and in that case these Breakthroughs might be worth spending lab time on.
Most of the time, though, these should be skipped unless they're very specifically being offered as a Covert Op where you have no better options available. (eg you're near the beginning of the game, and what few alternate Covert Ops are available are more hazardous and/or also low in value)
Guerrilla Tactics School Construction
The Guerrilla Tactics School Facility costs half as much to construct.
This is one of the most pointless of the Facility cost reduction Breakthroughs, as the GTS is one of the first Facilities you should have online in any run that isn't some bizarre gimmick run or distorted by mods or ini editing. As the game only offers you Breakthroughs for Facilities you currently have the ability to build and the GTS is, like most Facilities, not possible to have more than one copy of, you're extraordinarily unlikely to even see this Breakthrough unless you pour literally hundreds of hours into War of the Chosen or deliberately avoid building the GTS early for reasons like 'using mods that make it less important'. (Or going for 'The Few and the Proud', the Achievement for beating the game without buying squad size expansions, making the GTS less of a priority...)
Indeed, the first time I did roll this, it was still pointless, because it had shown up in my initial Covert Op pool and by the time I had the Resistance Ring online to go for it I'd already started building the GTS.
It's not like the GTS is particularly expensive, either. Sure, Supplies are tight in the early game, but this is still pretty underwhelming. I'd rather have had something like an additional slot for training Rookies, or even better it would've been cool if Live Fire Training had been a Breakthrough instead of a Resistance Order.
On the plus side, you don't have to worry about it clogging up your research or Covert Ops. It's merely virtually pointless that it exists, not actively impacting a typical run in a negative way.
Oh, and yes, this being the exact same graphic used for Future Combat I and II is, in fact, what goes on in-game. I get the impression the Breakthroughs system was one of the lower priorities in development, which is unfortunate because it's one of the more fundamentally compelling systems War of the Chosen adds.
Training Center Construction
The Training Center costs half as much to construct.
I spent literally years unable to parse this graphic. It's probably meant to be a brain in front of two crossed rifles, but it... doesn't parse readily.
Regardless, much like the GTS version you're fairly unlikely to see this in practice, as the Training Center should be one of your fairly early priorities. I frequently build it as my third facility; Resistance Ring, then GTS, then Training Center. Getting higher-tier Bonds going faster is very useful not only for the essentially free tactical combat value but also for accelerating Covert Op turnaround, and while it's generally not viable to buy your first bonus skill until about Lieutenant once you are at that point the effect can be pretty huge. You also need the Training Center built to be able to even see how many bonus skills most of your soldiers have, let alone what skills they specifically have. A soldier with their bonus skills stacked early and obviously great is less of a gamble than a soldier with them stacked late and still completely unknown, and having that info early can be useful when forced into a situation where you have to decide who is liable to get killed, or who to send on Covert Ops with a high Capture Risk.
Training Center Construction isn't borderline-pointless the way Guerrilla Tactics School Construction is, as there's solid arguments for putting off the Training Center until later (eg Resistance Ring, then GTS, then Proving Ground), and the Training Center costs more; saving 63 Supplies isn't huge, but it's better than saving 43.
But it's still something you'll only rarely even see.
Power Conduit Construction
The Power Conduit upgrade for Power Relays costs half as much.
This is an okay facility-related Breakthrough. Most runs will end up building two Power Relays, and many of them will end up upgrading both of them as well, and if you're waiting to be able to build them on Exposed Power Coils it'll generally take a couple of months -much longer, on Legend- to get even your first Power Conduit built. This means you have a decent amount of time for it to get offered before purchasing what it affects, and while Power Conduits aren't expensive if you're buying two of them you'll end up saving 80 Supplies, which is better than eg Training Center Construction. Furthermore, you're normally building your first Power Relays in the phase of the game where lab time is somewhat less precious and Supply crunch is noticeable; it may actually be a good trade-off to make.
I'd have rather it was a Breakthrough that increased how much Power you got out of Power Conduits/Power Relays, but this isn't terrible. I usually ignore it, but there's decent arguments in its favor.
Elerium Conduit Construction
The Elerium Conduit upgrade for Power Relays costs half as much.
Yep, another reused Breakthrough graphic.
I virtually never build Elerium Conduit upgrades. In a normal run you don't have the Elerium Crystals to spare, particularly on Legend, and just building Power Relays on your two guaranteed Power Coils is enough to ensure plenty of power for the Avenger in conjunction with Engineers manning slots and upgrading one or both with Power Conduits. This all costs primarily Supplies, which are always much easier to come by than the Elerium Crystals the Elerium Conduit upgrade demands.
This is a roundabout way of saying Elerium Conduit Construction is borderline worthless of a Breakthrough. Particularly frustrating is that it'll tend to semi-regularly clog your Covert Ops or waste a lab Breakthrough trigger, since there's no point where you've made it permanently, inarguably irrelevant.
That said, cost reduction Breakthroughs do affect how many Elerium Crystals a facility costs, where applicable. So that's... something, I suppose.
To be honest, I don't even understand why this Breakthrough exists. Elerium Conduits were extremely dubious in the base game, and War of the Chosen has provided tools to speed up facility construction, speed up Excavation, and also provided new ways to make your Power go further, like burning Covert Ops on adding Contacts so you don't need as much Resistance Comms support, making it even less likely you'll bother with Elerium Conduits. In the base game, I could imagine having circumstances conspire such that an Elerium Conduit was actually the best solution to a bad situation. In War of the Chosen, it's virtually impossible for circumstances to line up that way.
It's not like halving the upgrade's cost addresses the reasons why it's close to worthless, either.
I just don't get this Breakthrough.
Resistance Comms Construction
Halves the cost of building the Resistance Comms facility.
This is potentially decent. You can't really count on it being good, but if you end up building two Resistance Comms it will save 110 Supplies, which isn't bad, and like Power Conduits you're often building your first Resistance Comms in the phase of the game where lab time isn't urgently valuable and Supply crunch is probably happening.
I say you can't really count on it, though, because in War of the Chosen you often don't actually need a second Resistance Comms facility. Most runs only end up needing 8-12 Contacts to hit the Forge and Psi Gate missions and hit Avatar Project Facilities enough to avoid a game over, you start with 3 Contacts, and building, upgrading, and fully manning a single Resistance Comms will provide 8 more Contacts. 11 Contacts is often enough for your needs...
... and in War of the Chosen, if you prioritize chasing Contact boosts from Rumors and Covert Ops you'll often get 3 more Contacts before you're in the endgame. (Or you could get Resistance Rising I or II!) It's extraordinarily unlikely you'll need more than 14 Contacts in a run, even if you put off the Shadow Chamber and its projects a fair amount. At which point, why bother making a second Resistance Comms? 55 Supplies isn't nearly so solid a savings.
Indeed, I've had a couple of runs that got so many Contacts from Rumors, Covert Ops, and Resistance Orders I never built any Resistance Comms!
And conversely, once I got a handle on War of the Chosen, it became very rare for me to build a second Resistance Comms.
So like I said: potentially decent.
But honestly... not likely.
Additional Comms Station Construction
Halves the cost of upgrading Resistance Comms with an additional slot.
Upgrading Resistance Comms costs 125 Supplies a pop. Potentially saving 125 Supplies isn't bad.
Unfortunately, as I just covered, it's pretty unlikely to happen. Even if you do build a second Resistance Comms, you're quite unlikely to upgrade both of them; you'd basically need to have bad luck on Engineer recruitment simultaneous to having a desperate need for additional Contacts for it to be liable to actually happen.
As such, this is usually something you should skip, particularly if it shows up in the lab.
UFO Defense Construction
Halves the cost of building the Defense Matrix facility.
Uh. Yay?
Saving 37 Supplies is pretty underwhelming, and the Defense Matrix is one of those Facilities you're likely to either start building immediately after unlocking it, or decide you don't care and never build it ever.
Also, I'm not sure why whoever came up with this icon thought it was a good idea to depict a Turret from the front, because it is not at all obvious that this is depicting a Turret.
This Breakthrough deeply confuses me.
Quad Turrets Construction
Halves the cost of upgrading the Defense Matrix facility.
Upgrading a Defense Matrix is also 75 Supplies, so this is also lackluster savings, and even more so than the basic Defense Matrix this is generally an upgrade you either take immediately or never take. (Or more precisely, you probably build the Defense Matrix and upgrade it the instant it's finished, or you don't bother to build it at all) So you'll virtually never see this Breakthrough, full stop.
I mean, the Defense Matrix is at least worth building in War of the Chosen due to the combination of 'now Turrets gain Squadsight if the Defense Matrix is manned' and 'now you have decent odds of benefiting more than once in the entire game' and 'Chosen Sabotage is substantially more likely to fail if you have a Defense Matrix', but these Breakthroughs are still pretty bizarre and dubious.
I'm honestly surprised they weren't, instead, the way you boosted Turret damage. Or a way to boost their Aim, that would've been very nice. Just say it's a Breakthrough related to their target-acquisition algorithms, there you go, it makes sense narratively and is more useful in gameplay.
Ah well. At least it won't actually clog things up, generally speaking.
Psi Chamber Construction
Halves the cost of building the Psi Lab facility.
This is one of the relatively decent facility Breakthroughs, between the Psi Chamber being on the expensive side for a facility -125 Supplies and 20 Elerium Crystals- and sufficiently demanding Power-wise that even if you want to build it right away you may be forced to wait long enough for this to actually appear, in part because it can be unlocked extremely early; you just need the Sectoid Autopsy to get started on Psionics, and once Psionics is researched Psi Chamber Construction can pop in anytime until the Psi Lab is started. Still not great, but decent.
The saved Elerium Crystals is particularly appreciated if playing on Legend, freeing up more for beam-tier equipment upgrades, and Legend's much slower Excavation and facility construction also means you're even more likely to have Psi Chamber Construction offered in a timely manner. I wouldn't go so far as to call it a must-have, but if you were planning on building a Psi Lab regardless, it's certainly worth considering spending a Covert Op on it, maybe even lab time.
Second Cell Construction
Halves the cost of upgrading the Psi Lab facility.
If you're going to bother with Psi Operatives at all it's usually best to get the second slot, to maximize the payoff for your investment. Picking this up via a Covert Op is certainly worth considering right there, and fortuitously the Psi Lab upgrade costs 225 Supplies and 15 Elerium Crystals; that's more Supplies than building it in the first place! That's pretty good savings, particularly since this includes that it saves you 8 Elerium Crystals.
Its main flaw is that it can't be offered until the Psi Lab has been finished, and it's not at all unusual to be able to upgrade the Psi Lab the very instant you have it built, and if you're going to upgrade it at all it's desirable to do so as early as possible. As such, there's often no opportunity for it to be offered at all.
Still, you can end up building the Psi Lab, not having the Power to upgrade it, and get offered Second Cell Construction before you hit that point. It's merely unlikely to appear, not virtually impossible.
Laboratory Construction
Halves the cost of building the Laboratory facility.
63 Supplies saved is okay, just as with the Training Center and whatnot, and notably the Laboratory is available to build right away but probably shouldn't be built initially since it's only really worth it once you have multiple Scientists. Which means Laboratory Construction gets a fairly long stretch of the game to be thrown at you before you get around to actually building a Laboratory, giving it better odds of actually helping than a number of these facility-related Breakthroughs.
I wouldn't burn lab time on it, but I'm okay with burning Covert Op time on it if no Supply Run is available, or if it's faster than the Supply Run that is available, or the like.
Additional Research Station Construction
Halves the cost of upgrading the Laboratory facility.
This is also 63 Supplies saved, but is substantially held back by the fact that the usual thing to do with a Laboratory is to upgrade it the very instant it's finished, meaning you're extremely unlikely to ever see this Breakthrough offered, let alone actually take advantage of it.
Oops.
Workshop Construction
Halves the cost of building the Workshop facility.
...
yay?
Unfortunately, the Workshop is extremely dubious. On difficulties below Legend, you're not under that much time pressure and will generally eventually get more Engineers than you know what to do with so long as you pursue Engineer-providing Rumors, missions, and Covert Ops as a modestly high priority. On Legend, time pressure is significant for much longer, but so is Power pressure, such that it's difficult to justify trying to squeeze a Workshop in somewhere early in your construction and Excavation. By the time you can slip a Workshop in, you don't really need one anymore. It's also very difficult to arrange an optimal Workshop-friendly facility distribution even when you know what you're doing, further reducing the appeal of actually building a Workshop.
All of which means that saving money on building a Workshop is dubious on every difficulty.
Which is too bad, because the Workshop is expensive. Halving its cost is saving you 125 Supplies, which is notably more than a single Supply Run can possibly provide. If the Workshop was reliably worth building, this would be an actually worthwhile Breakthrough to grab!
Additional Workbench Construction
Halves the cost of upgrading the Workshop facility.
See previous; upgrading the Workshop is actually fairly pricey, so this should be a good deal, but the Workshop itself is almost never worth building, and it's even rarer for it to be worth upgrading. Only Resistance Comms and Power Relays can have more than one Engineer assigned, and it's only possible to surround the Workshop with four facilities if it's placed in the upper-middle or lower-middle slots; this makes it a pain to actually get the Workshop situated so you can leverage the full four Gremlins, and often arranging for such conditions means damaging your build some way or another, whether it's delaying initial construction of essential facilities or sub-optimally placing the Workshop on an Exposed Power Coil or tearing down and re-building essential facilities later.
ie this should be a good Breakthrough, but is actually awful.
Not helping is that, as usual, you can only be offered it after you've finished your Workshop. If you could get both Breakthroughs ahead of time, you might at least get both Breakthroughs via Covert Ops and as a result pursue the Workshop, at least in theory.
Infirmary Construction
Halves the cost of building the Infirmary facility.
Well, you should build the Infirmary in every run, even if it's fine to put it off a bit. If you can get this from an early Covert Op, it's kind of like getting some Supplies.
I personally wouldn't burn lab time on it, but from a Covert Op? Sure, why not, assuming that cramming it into my Covert Op schedule doesn't get in the way of other things I care about.
Hypervital Module Construction
Halves the cost of performing the Hypervital Module upgrade for the Infirmary.
Yay?
The Hypervital Module is extremely dubious a purchase, and halving its cost doesn't actually do anything to address its deficiencies. It's not even that many Supplies being saved; 40 Supplies. That's it.
It's actually fairly annoying to have this clogging up Covert Ops or popping into the lab... which is frustrating since making the upgrade is a complete waste, so good play will be consistently having this waste Breakthrough opportunities.
At least the Hypervital Module is new. Overestimating its value is reasonable, and it does sound like a solidly useful concept in principle, where I can see how the devs thought it would be good enough to bother building. This Breakthrough is bad, but I can understand how it happened, unlike some of these Breakthroughs that are just plain confusing.
Digital Network Construction
Halves the cost of performing the Digital Network upgrade for the Resistance Ring.
Note that there are two upgrades at the Resistance Ring, and this only effects the cheaper one. In practice it's saving you... 50 Supplies.
This can be an okay benefit from a Covert Op, such as if none of your other Covert Ops is offering Supplies anyway or you really want the soldier boost being offered, but it's extremely difficult to justify spending lab time on it. It does benefit some from the fact that it's usually best to put off upgrading the Resistance Ring until you're in the part of the game where Supply crunch is a factor. Not a lot of benefit, but some.
Holo Planner Construction
Halves the cost of performing the Holo Planner upgrade for the Resistance Ring.
Yeah, it's yet another recycled Breakthrough graphic. This one is particularly puzzling, since just removing the arrows or halving the number of arrows would immediately make for a slightly distinct graphic, and the game is willing to do exactly that to separate out graphics. I suspect some manner of oversight occurred here, because it seems likely that with-arrows is a modified version of a without-arrows graphic that inexplicably isn't used; it'd be easier to add arrows in to a no-arrows graphic than to remove arrows from a with-arrow graphic, after all, and that's how these things usually go.
In any event, this is saving a whole 63 Supplies, and so is maybe okay to grab via a Covert Op but is still usually a waste of lab time. It also can't be offered until you've purchased the Digital Network upgrade, and it's entirely possible to end up purchasing both upgrades at the same time. Even if you don't, this makes it that bit less likely you'll get it at all.
On the plus side, the game doesn't have a Resistance Ring cost reduction Breakthrough. That would've been downright appalling, given the game itself clearly wants your very first building to be the Resistance Ring, and is completely justified in pushing that. I kind of suspect that at some point in development such a Breakthrough did exist, probably using a no-arrows version of this graphic and got removed because yeah that would be awful to include, only nobody thought to shuffle the no-arrows graphic onto Digital Network Construction. Oops.
Shadow Chamber Construction
Halves the cost of building the Shadow Chamber.
You'll basically never see this. It can't be offered before you complete Alien Encryption, and you can't put off building the Shadow Chamber for very long unless you get multiple Sabotage Covert Operations very early on because you'll be risking a game over if you put it off. I only saw it by deliberately fishing for it, for screenshot purposes.
Furthermore, delaying building the Shadow Chamber means both delaying your ability to actually advance toward the endgame and means delaying access to enemy unit previews. So even aside the 'build it quick or game over' aspect, you'd want it built fast just to avoid the game taking unnecessarily long and to get access to its mechanical benefits early, particularly as later enemies are kinda designed around the assumption that you do, in fact, have the Shadow Chamber to let you plan for them properly.
Like most of these facility-related Breakthroughs, should you happen to be whatever tiny percentage of people ever see it, it's... okay as a Covert Op grab, and dubious for spending lab time on. 63 Supplies is, as usual, not great but not terrible.
I really think these facility Breakthroughs would've been a lot better if they slashed the Power requirements of their facilities/facility upgrades. Among other things, a big part of what makes the early game repetitive is your tiny Power budget; you start with just enough spare Power to fit in two essential structures (Resistance Ring+GTS) and then a third structure you can actually get away with varying. Breakthroughs that provided more freedom regarding the Power situation would potentially let you squeeze in facilities or upgrades you'd normally put off. It would also have a clear, permanent payoff; the facility Breakthroughs are lower in value than eg the damage boosting Breakthroughs in part because a modest resource savings fades away in importance once you reach the point of having more Supplies than you know what to do with, where damage boosts are forever. (Aside that Conventional and Magnetic damage boosts will eventually be obsoleted, but their benefits are so huge during the phase they apply it's fine they eventually stop mattering) Less Power demands would mean less pressure to build Power Relays, the ability to free up Engineers from manning Power Relay slots and focus their efforts elsewhere and in turn less pressure to aggressively recruit Engineers, and with enough such Breakthroughs accumulated you might not even need the second Power Relay!
That would make facility-related Breakthroughs change the course of the average game in a large, obvious manner. Halving costs is... not nearly so meaningful or interesting.
Rapid Excavation
One time, you can instantly excavate a single room in the Avenger without need of an Engineer.
This is the unambiguously best of the facility-related Breakthroughs, dramatically accelerating your facility timetable if used properly -especially on Legend, where excavations not in the top row take three times as long as below Legend- while providing an immediate injection of resources and allowing you to distribute Engineers to facilities you might otherwise neglect until later. (eg the Resistance Ring) Don't waste it on one of the spots that only takes one or two Engineers at max: use it on an Exposed Power Coil or some other spot that will take up to three Engineers to dig open. That maximizes its value (The more Engineers a location can support, the longer it takes to Excavate, and the bigger the Supply and Alien Alloy payoff if it's not an Exposed Power Coil), and will almost always be more helpful than using it on a closer spot that requires fewer Engineers.
The game itself doesn't explain how you use it, but it's fairly intuitive; normally when you pop into a room that can currently be dug out, the Excavate button will be dark until you assign some Engineers. If you have Rapid Excavation ready to go, it will be in the lit-up green state even with no Engineers assigned; if you attempt to start an Excavation without assigning an Engineer, the game will ask if you want to use up the Rapid Excavation charge, and if you say yes the room will be instantly cleared. Alternatively, you can assign Engineers as normal and then click the Excavate button, in which case it will be Excavated as normal.
Also nice is that it won't be offered once you're done Excavating the Avenger. No having to worry about it wasting Covert Op slots or lab Breakthrough chances at that point.
This is the only Breakthrough I always take if it shows up in the lab. (Well, I wouldn't if I had plenty of Engineers and only one spot to Excavate, but that hasn't happened as yet) Instant resources, dramatic acceleration of your facility timeline, and less pressure to recruit more Engineers is a fantastic set of benefits, and the accelerated facility timeline can benefit you in so many different ways it doesn't really matter what your most urgent concern is, Rapid Excavation is helping. It's particularly excellent if it shows up when you're still working your way to your first Exposed Power Coil, but even once you've got your first Power Relay on an Exposed Power Coil built it's still the best of the facility-related Breakthroughs by a fairly wide margin.
It's also unique and interesting, instead of being one of several Breakthroughs that are the same basic idea applied to different specific things, which is definitely a big part of why I like it. I'd be an even bigger fan of Breakthroughs if more of them were original like this.
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Overall, the Breakthroughs idea is better in concept than execution, a system for greater variety when replaying the game that ultimately has a large number of its options too low-value to be all that worth considering and too low-impact to be all that interesting in practice, plus several options you will basically never see even though you want to use them, but even with its underwhelming execution it manages to do a pretty solid job of making War of the Chosen a more varied and interesting experience than base XCOM 2.
I'm hoping that XCOM 3, whenever it comes along, brings back the basic idea. With some refinement like replacing dud Breakthroughs, adding in new Breakthrough concepts that have an interesting impact on runs, and so on, it could be an incredible system for helping ensure each new run is a fresh experience for many, many runs.
Inspirations, meanwhile, really depends on how XCOM 3 handles its tech tree. If it falls in the same basic mold as XCOM 2 and its predecessor, Inspirations would remain a neat idea that's dull in practice. If XCOM 3 broadens your research tree so that enhancement comes from spreading out into multiple realms rather than essentially-linear advancement down a narrow pair of lanes that are partially intertwined, then Inspirations could become an excellent way to enhance replayability by making different runs end up prioritizing different things.
Also, it's worth pointing out that this isn't the entirety of what War of the Chosen does with research. In addition to the new Autopsies, some old Autopsies have been made prerequisites to existing researches that, in the base game, didn't require them. I certainly appreciate the idea, as for example it's nice on a thematic level that studying Mutons is now necessary to work out how to build your own powered armor, though in practice the exact choices are a bit... centralizing. More on this when we get to the enemies in question, though.
Next time, we cover one of War of the Chosen's less ambitious, but still random and interesting systems; Sitreps.
See you then.