FTL Analysis: Subsystems

Subsystems are simpler than Systems, so I'm covering them first.

There are four Subsystems, and every ship can potentially equip all of them at once. You don't need to worry about running out of Subsystem space or anything like that. Subsystems don't use general Reactor power, meaning they're always running if not critically damaged or Ionized, and also meaning that comparing upgrade costs in Systems and Subsystems is deceptive because generally if you're upgrading a System you're also upgrading your Reactor to power the upgrade, meaning Subsystems cost less than equivalent on-paper Scrap costs on System upgrades.

In addition to the explicit benefits of upgrading Subsystems, Subsystems gain 'System HP' for being upgraded. That is, level 1 Piloting will stop functioning entirely if it ever takes damage from a weapon, or if a fire or boarder is allowed to do a full bar of damage. (If a boarder does less than a full bar of damage and then leaves the room or dies, with no other boarders in the room? The damage will be instantly undone for free... assuming there's no fire doing ongoing damage, anyway. Same for if a fire goes out partway through doing damage, assuming no hostile crew are in the room) Said System HP is actually working through the upgrade tiers: a level 2 Piloting that takes 1 damage will now perform as level 1 Piloting until repaired or damaged further, whereas if it takes 2 damage at once it will be completely destroyed, and a level 3 Piloting that takes 1 damage will function as level 2 Piloting vs 2 damage causing it to function as level 1 Piloting, etc.

Repairing Subsystems -and Systems, but we'll get to that- is, it should be noted, free, aside crew time. It doesn't cost Scrap. In line with that, your crew will autonomously begin repairs on any damaged System or Subsystem they're standing in unless otherwise occupied -note that performing repairs prevents manning the room until completed.


Piloting
-/20/50
Autopilot: 0%/50%/80%
When no one is in the room, the FTL Jump won't charge, and evasion will be reduced by a percentage determined by the Piloting Subsystem's level. Conversely, Piloting's behavior when manned is unaffected by upgrades.
When manned, the ship gains +5/7/10 evasion, based on the crewmember's Piloting skill.

Note that the 'autopilot' effect's percentage of retained evasion does not interact with the evasion bonus for having Engines manned. That is, if you have 20 evasion from Engines and 10 evasion from somebody manning Engines, level 2 Piloting with no one inside of it will leave you with 20 evasion, not 15.

Also note that Piloting has the extremely unusual quality of distinguishing between 'in the room or not' and 'manned or not'. That is, if someone is in Piloting, but is currently busy repairing it, closing a breach, fighting a fire, or fighting enemy boarders, the FTL drive will continue to charge and your ship won't lose any evasion... except for the evasion bonus for manning Piloting in particular. Every other System or Subsystem only cares about one or the other, if it cares about either.

Also note that, inexplicably, the FTL Jump will never charge if no one is in Piloting, not even once you've upgraded it and so it has an autopilot. This makes absolutely no in-universe sense and I can't think of a single legitimate game design reason for it, but it's true regardless. More sensible is that you can't activate an FTL Jump if no one is in Piloting. In conjunction with always losing evasion if no one is in Piloting, you should basically always have someone in Piloting if you can.

Anyway, upgrading Piloting is... limited in its utility. Upgrading it once has the benefit of making it so your ship doesn't completely lose evasion and stop charging FTL just because a random laser shot got through and hit Piloting, but the explicit bonuses are pretty useless since you should basically never have Piloting completely unoccupied for more than a brief period. Upgrading it a second time makes it actually tolerable to have it unoccupied, since your evasion isn't completely crippled, but it's still not great, and by the time you can afford to dump 50 Scrap into such a low-value upgrade it's generally the case that you're regularly facing ships equipped with eg Breach Missiles, so the extra hit point aspect is much less useful than you might hope. You also probably have enough crew there's no need to pull crew from Piloting in a pinch.

I mean, you might as well make the purchase in the extreme late game if you lack any better options, but generally Piloting isn't very worthwhile to upgrade.

It doesn't even provide a good supply of blue options; only 3, of which only one can even spawn outside Abandoned Sectors, and that one can only spawn in a Plasma Storm, and only a limited range of Sectors. Also, only one of these cares about level 3 Piloting. So... yeah. Blue options don't really help.


Sensors
40/25/40
Reveals your rooms at level 1. Reveals enemy rooms at level 2. Reveals current weapon charge on enemy weapons at level 3. Reveals enemy power distribution if manned at level 3. Doesn't function at all in nebula, and is capped at level 2 when fighting the Rebel Flagship. Manning Sensors raises its effective level by 1.

Note that the AI blatantly cheats and does not actually need Sensors for anything. This is reasonable and typical of games struggling with AI pretending to have limited information when it comes to points like 'instantly knowing where boarders, fires, and breaches are', and conversely the AI's behavior doesn't take into account any of the information Sensors reveals at its highest tiers, but this is rather conspicuous with Mind Control, which in player hands requires you have Sensors, a Slug, crew-or-Hacking-derived sight on a room containing enemy crew, or the Augment that reveals enemy crew, but in AI hands Mind Control has no need for any of that. This is particularly conspicuous in the case of the Autoship variant that has Mind Control, since it has no Sensors and no crew, so even if you lack Sensors yourself there's no possibility of there being Slug crew explaining this.

You can pretend to yourself they all have the Augment, I suppose?...

In any event, for the player Sensors is... janky.

First of all, upgrading Sensors is annoyingly dubious. Revealing enemy power distribution at the highest tier is completely worthless: it makes it really blatant how massively late-game ships cheat, but there is literally nothing you can actually do with this information. Revealing the current level of charge on enemy weapons isn't much better; you can do some things with this information, such as better timing Cloak activations, but not much. You can't target a particular Weapon to disable, so you're not going to target whatever is closest to a full charge. You don't have defensive tools that need to be activated shortly before attacks are on the way; Cloak is your only defense where you have control over timing. It benefits from being able to see clearly when a concentration of fire timings is happening to maximize Cloak-based dodges, but that's it; you already want to activate it after enemy weaponry has fired, and you can see weapons firing without needing Sensors.

Revealing enemy rooms is actually moderately significant... but still less than you might expect. You'll need Sensors upgraded or manned to use Mind Control if you're not boarding yourself, and if you're attempting to get crewkills with targeted weapon usage (Particularly the Anti-Bio Beam) you'll thus need Sensors upgraded or manned, but those are the primary values it brings to the table. Being able to see crew type is mildly helpful for boarding ships (So you can see how dangerous enemy crew will be to your boarders, mostly), and occasionally nice to know otherwise (Trying to burn out Rockmen is a futile endeavor, for example), but a lot of the time this info doesn't really matter.

Similarly, it lets you see breaches, fires, and oxygen status on the enemy ship, but this is surprisingly narrow in its utility. Occasionally you'll happen to be on the way to a crewkill where Sensors 2 will let you see you should stop trying to blow up the ship, but unless you're using the Fire Beam or especially Fire Bomb, you usually don't care about these tidbits: you're usually not going to stop shooting a System with lasers just because you started a fire in it or generated a breach.

The first level of Sensors is hugely important, meanwhile. You need it to be able to respond to boarders as soon as they arrive, to respond to fires before they have a chance to spread, to avoid sending crew through oxygen-less rooms or rooms on fire when they're low on health... this all matters a lot. There are things you can have that slightly reduce the importance of Sensors -a Slug crewmember will let you monitor boarders without needing Sensors- but it's nearly impossible to reach the point where Sensors 1 isn't adding value.

Which in turn means you still want to upgrade Sensors just to get the HP buffer to avoid losing the first-level benefits, even though the ostensible primary benefits of upgrading are so lackluster.

It's... not great design.

At least Sensors is pretty cheap to upgrade...

It does also have 17 blue options, admittedly. Notably, if you haven't unlocked the Mantis Cruiser A yet and want to be able to unlock it via completing its associated event, you'll need to upgrade Sensors or have a Crew Teleporter; most ships have Sensors built in, whereas only a few have Crew Teleporters and there's no guarantee of getting the opportunity to buy one.

Mostly, though, the Sensors blue options either tell you more accurately what the consequences of a choice will be (eg 'doing X will result in a fight in this particular case', as opposed to doing X and then seeing whether a fight rolled or not), or negate the possibility of specific worst-case outcomes. Both of these are low-value, and in particular suffer from the issue that you didn't necessarily actually benefit from upgrading Sensors; if you never rolled a worst-case scenario in the first place, upgraded Sensors warding you from such doesn't matter. It's also dubious to upgrade to level 3 for blue options; the majority of Sensors blue options have the exact same outcome for level 3 Sensors as level 2 Sensors, making it fairly unlikely that upgrading to level 3 will ever matter.

There's a specific sub-event found on a few of these where advanced Sensors lets you make a second pass, and in those cases it actually is a concrete improvement, providing additional rewards you otherwise couldn't get. The collective collage of Sensors blue options are also common enough they are fairly likely to crop up if you upgrade Sensors early. So... upgrading can pay off in a clear way, just... very erratically.

Also note that level 1 Sensors has no blue options; if you're playing one of the ships that doesn't start with Sensors, don't buy Sensors on the idea of blue options unless you're confident you'll actually upgrade them.

Door Control
60/35/50
Required to manually control the open/closed state of doors. At higher levels, doors will delay boarders and fires for longer. Doors are locked by default at level 2 and up, delaying boarders. Manning Doors ups its effective level by 1.

Door 'HP' is dependent not only on the Door Control level, but also on difficulty... with the difficulty modifier affecting enemy door HP identically to your own, making boarding strategies a little stronger on higher difficulties. (Not much stronger; Door Controls are on only a handful of enemy ships)

Door 'HP' itself is a flat number of hits unaffected by crew combat ability. That is, crew don't break down doors faster if more experienced, and Engi are just as effective at bashing down doors as a Mantis, not the one-third effectiveness you'd expect. The values in questions are:

Easy: 12/16/20
Normal: 8/12/18
Hard: 6/10/15

(These being the level 2/3/4 values, since level 0 and 1 doors are simply walked through by enemies)

Also note that when manning or ceasing to man Door Control, current door HP is modified proportionately. ie if you're playing on Normal with level 2 Door Control, boarders are halfway through a door (4 hits away), and you then man the Door Control, it will increase to 50% more durability. (ie now 6) As such, it's best to pre-emptively man the Door Control, if you're going to man it at all.

Also note that while Door Control can be purchased, only the Rock Cruiser B has this as an option: every other ship starts with a Door Control installed. And it's not a very useful option on the Rock Cruiser B, since it has no external doors to vent atmosphere with; you're usually better off not bothering purchasing it, except perhaps late in a run that is running out of useful things to spend Scrap on.

Upgrading the Door Control is one of FTL's primary tough judgment calls of the early game. On the one hand, upgrading the Door Control makes a huge difference in your ability to fend off boarders, especially when they foolishly teleport into empty (At least of your crew) rooms that have external doors; with even just the first upgrade, it's often possible to fend off non-Lanius boarders without ever getting your own crew hurt simply by venting atmosphere, with them desperately trying to flee the encroaching suffocation and only somewhat delaying their death. (Or at least their retreat) It also does a lot to slow the spread of fires from one room to another. (Unfortunately, I don't have precise numbers on this particular functionality, but it's pretty noticeable)

On the other hand, 35 Scrap is a painfully large chunk of change from an early game perspective. Notably, that's a substantial fraction of the cost of a crewmember, who can man the Door Control to get most of the benefits of upgrading it while also being able to more directly fight boarders and fires or otherwise contribute. On the third hand, crew fighting fires, fighting boarders, closing Breaches, repairing System damage, or that are Stunned can't man the Door Control; relying on manning the Door Control has more risk of your doors becoming unlocked at a problematic time than if you upgraded it, such as if you get a boarding event while fighting a ship with a Crew Teleporter and one or the other drops crew into the Door Control. Suddenly the other batch is free to wreak havoc instead of suffocating to death, whoops!

On the fourth hand, enemy ships can't have a Crew Teleporter or Boarding Drone really early in a run, and even once they're possible they're not common. Boarding events are always possible, but far from guaranteed; it's entirely possible to decide to upgrade the Door Control and have it never actually help in a run!

This makes for a surprisingly nuanced judgment call I actually enjoy a decent amount, which is a pleasant surprise.

Annoyingly, Door Control is extremely limited in its blue options. There's two refueling station events where it can safely provide some Fuel, and that's it -notably, upgrading to Door Control 3 is unnecessary, so if you feel Door Control 2 is adequate for combat purposes blue options aren't a reason to upgrade further. I don't get why Door Control is so limited on blue options; there's quite a few events where it would make sense for Door Control to have some kind of benefit, but it just... doesn't.

Backup Battery
35/50
Power: 2/4
Generates Power for 30 seconds, with a 20 second cooldown after it's done. This Power is assigned last, and removed first, whether the player is manipulating Power assignment or automatic effects are.

The only Subsystem to be added by the advanced edition update.

It's honestly kind of disappointing. It's worth considering late in a run, when an individual Reactor bar costs 35 Scrap, given Subsystems don't have a slot competition aspect, not to mention it is possible to end up with greater Power demands than your Reactor can cover, but temporary Power generation is... not great, unless you're perfectly happy to be mildly exploitive and only use it for eg Mind Control, where the Power going away is actively an advantage by reducing the cooldown.

It doesn't help that your ship doesn't necessarily need even the full Reactor Power... why buy yet more Power if you're set for endgame on Power needs as-is?

As best as I can tell, the idea behind the Backup Battery is to make Ion Storms less painful, but it's lackluster at this task if that's the idea. The fact that it generates a flat (And low) Power amount is particularly harmful to its effectiveness; really early in a run, when its Scrap cost is painful to cover (And you can't get a free Backup Battery from events, note), 2 or 4 Power can potentially cover most or all the Power lost to an Ion Storm. Late in a run, when you already have 20+ Power, you'll still be down a lot of Power; frankly, I don't understand why the Backup Battery doesn't scale off your Reactor level. An upgraded Backup Battery providing 50% of your Reactor output would make it a natural (But still imperfect!) 'counter' to Ion Storms, just generally bolster its relevancy, and ensure Reactor upgrades have primacy regardless, no risk of players using the Backup Battery to 'cheat' on Power progression.

As-is, if you want the ostensible benefits of a Backup Battery, Zoltan crew are a better purchase 99% of the time.

Bizarrely, the Backup Battery has zero blue options. So that's not a reason to buy and upgrade a Backup Battery, never mind that there's a fair few events it would make sense for it to offer a blue option.


Reactor
30x3/20x5/25x5/30x5/35x5

The Reactor isn't really classed as a System or Subsystem. It doesn't sit in a specific room in the ship, can't suffer damage to impair its performance, etc. I'm placing it in the Subsystem post because it's more like a Subsystem than a System; after all, the primary distinction between the two is that Systems require Power, when the Reactor provides that Power, and so obviously can't require Power. Also because there's so few Subsystems; better spacing this way. It's not like the Reactor merits a post to itself...

Unlike Subsystems and Systems, upgrading the Reactor only increases the cost per step every fifth step, hence the unusual formatting for the Scrap costs. Furthermore, only the Zoltan Cruiser C has a weak enough Reactor to ever see the lowest three purchases; every other ship starts with at least 5 Power, and usually it's more than that.

The Reactor itself isn't an element that involves much mental engagement. There's a little room for judgment calls and learning the game, in the sense that you can do a certain amount of upgrading Systems without necessarily upgrading the Reactor in lockstep, but only a little; mostly it amounts to a kind of hidden cost, where a System effectively always costs more Scrap to upgrade than its 'on-paper' numbers.

In practice, I'm honestly not sure what design purpose the Reactor could be said to fill. There's implications I could comment on, but in the end I'm not sure anything of real significance would be lost if the Power requirement on Systems was simply dropped and Scrap costs tweaked to offset this loss. It does technically put an overall cap on how much System upgrading you can truly benefit from at any given moment, but you already have a cap on how many Systems you can equip and how far you can upgrade an individual System, with most Systems having fairly low maximum Power demands. Furthermore, several Systems have little benefit from being fully upgraded, and/or from being fully Powered; as previously covered, the Drone Control is actually very difficult to ever use its full 8 Power, while Oxygen has limited conditions in which more than 1 bar of Power is beneficial to invest in it, as a couple of the particularly glaring examples. As such, it's actually pretty easy to have a run not care about there technically being an overall cap to how much Power a ship can have available.

Removing Power would require an overhaul to the Zoltans given their primary gimmick is based on Power, but it's kind of an awful, clunky gimmick as-is, so that's not really an argument for keeping Power in. Similarly, Ion Storms would have to be dropped or do something completely different, but given how design-awful they are that's, again, not really an argument for keeping Power.

To be clear, what I'm driving at it not so much 'Power should've been cut', so much as it is that I'm using 'what if no Power?' as an illustration of how its purpose in the design is somewhere from 'vague' to 'non-existent'. That I can't think of a single truly substantial loss that would be caused by removing Power as a mechanic is indicative of how meaningful the Power mechanic is: not very. It's simply too redundant with all the limitations on Systems; the need to upgrade the Reactor to power your upgraded Shields isn't meaningfully different from just making Shields cost more Scrap to upgrade in the first place while having no Power mechanic.

It's one of the more glaring flaws with FTL's design.

As a further layer of dubiousness to the whole thing, it should be noted that the AI blatantly cheats in regards to Reactor output. The player is limited to a maximum of 25 Reactor bars to spend into Systems. Late-game AI ships can easily have more than 40 Power. ("Wait," you might be thinking. "Didn't you say earlier that the player doesn't necessarily need a full 25 Power?" Yeah, there's even more cheating involved; that's for next post) As far as I can tell the AI literally assigns itself exactly as much Power as its Systems can maximally use; as such, the AI technically operates on Power rules like you do, but this only ever is meaningfully true in Ion Storms. And since the player should generally not actually have enough Reactor bars to power everything all the time, the AI is usually pretty strongly advantaged in Ion Storms anyway.

It's... not great design.

Also, upgrading the Reactor doesn't contribute to blue options. This is probably for the best design-wise even if it seems a little questionable from a realism perspective -my primary complaint is that Power-using equipment doesn't need to be powered or even be possible for you to power to benefit from the blue option; you've got a Glaive Beam equipped but are incapable of actually turning it on? The game doesn't care when it comes to blue options.

It's admittedly not a common issue, but it's pretty eyebrow-raising when it does come up.

A secondary complaint is it's one more example of Power not really mattering. Since nothing cares specifically about Reactor strength, Reactor strength per se doesn't matter, returning to the 'what is the point of this?' question.

------------------------------------------------

Next time, we move on to Systems, specifically the Systems that are not exclusive to advanced edition.

See you then.