These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: FTL: Faster Than Light
Send the crew to help immediately! YMMV tropes are no joke.
Of particular note is the Engi theme. On the sector map, it is an extremely sedate (if tense) piece, one which is difficult to imagine overlaying anything over it to produce a battle theme. Yet like the other themes of the Variable Mix, it does just that. That alone is grounds for awesome, but the Engi battle theme is also one of the best in the game.
Last Stand is that kind of piece to get you pumped to go out and rip that Flagship to shreds.
One of the random events is a bit funny about this. But ultimately in short, you are attacked by the Zoltan, you fight them off, and then the ship hails a cease fire, as it turns out, it's Captain was testing you, to see if a diverse crew could work together and protect your ship, and since you just did, he joins you.
Demonic Spiders: Just about every ship in the game has a certain strategy it's just not cut out to handle, at least until you somehow acquire the hardware and/or crew to make up for starting deficiencies. For instance:
Boarding parties, especially Mantis boarders or large 4-man groups, for ships that start off with small and/or combat-incompetent crews, which include:
Both Engi cruisers (Type A has two Engis and a Human, Type B has just a single Engi), seeing as Engis do half-damage in combat. The Type A, however, has a Medbot Dispersal augment to help its crew in combat, and the Type B can be run almost completely depressurized (outside of the cockpit) once you get blast doors, and until you get extra crew, as its "crew" of internal drones don't need oxygen.
Both Zoltan cruisers. The Zoltans are the most fragile race and moving them around results in ship systems losing or redistributing power, resulting in weapons getting canceled, cloaks getting deactivated, etc. Their Zoltan Shield augment can prevent enemy ships from using their teleporters or launching boarding drones while it's active, but various events have your ship randomly boarded anyway, with the game Lampshading how this shouldn't be possible.
Both Slug cruisers. It's not quite as bad for them since they can telepathically track the enemy boarders, and the Type A helps its two-Slug starting crew by being pre-equipped with blast doors. The Type B though has no starting medbay, and it depends on its Healing Bursts to keep its three-Slug crew alive, so if weapon systems go offline or you run out of missiles, you have no way to heal your crew.
Both Stealth cruisers. With no shields, evasion and cloaking are their main form of defense, and they need their systems to be manned more than any other ship. The Type A, though, has a crew of three Humans, while the Type B has two Humans and a Zoltan with only a two-square medbay. Boarding parties in your cockpit are bad for any ship, but are worse for the Stealth ships because you lose evasion and can take hits even when cloaked.
To a lesser extent, boarders are also problems early on for the Kestrel A, the starting ship, which also has 3 Humans, and the Federation Cruiser B, which has a Human, a Slug, and a Zoltan.
Attack drones and beam drones for any ship that doesn't have a proper shield system, seeing as the drones have higher damage-per-second than regular weapons at the cost of burst damage capability, and are hence particularly lethal against unshielded targets. This includes both the Stealth cruisers, and to a lesser extent the Type B Zoltan cruiser. The Stealth ships cannot conveniently cloak away from the almost continuous drone fire like they can with ship-to-ship weaponry volleys, so hull damage becomes inevitable. With the Stealth A (Nesasio), you can still go under cloak early and try to take out the enemy drone control with your first volley. But with the Stealth B, you have to wait and suffer, and if your weapon systems are hit, your power-hungry Glaive Beam goes offline and your only option is to try and run. The Zoltan B has temporary protection with its Zoltan shield but drones tend to tear through it fairly rapidly, but like a cloak, this still buys you some time to charge your weapons and try to disable the enemy's drone control. The Zoltan B also has it easier since it can acquire regular shields earlier than the Stealth cruisers can.
Zoltan Shielded enemy ships for any ship whose direct-damage offensive capability is either completely dependent on missiles (Rock A, Slug B), or just flat out non-existent (Mantis B, Unidentified B). It costs 3 Artemis missiles to break the overshield, which is equivalent to 18 scrap in stores and hence makes fighting Zoltan-built ships more expensive than it's worth in early game. And ships that start with no weapons at all have no option except to run, since the shield blocks out teleporters and boarding drones. The Stealth B also has yet another weakness in the early game against well-armed Zoltan shielded ships; it's not cost prohibited but rather time prohibited. The Stealth B depends on One-Hit Kill tactics with its Glaive Beam to prevent (most) damage in the early game, but the Zoltan shield flat out absorbs one blast of the Glaive Beam and leaves the shieldless Stealth B wide open to attacks for a terrifying 20 seconds before either its weapon or its cloak can recharge (providing they don't get disabled by then).
Ion Storms, a randomly occurring environmental effect in Nebula nodes. Running into one cuts your reactor output in half and depowers systems at random accordingly. This works on your enemy, too, but they can generally manage greater reactor output than you can. When you have to juggle power between your weapons, shields, engines, and life support, you can expect the enemy waiting for you to put some big holes in your hull before you make it out of there. Fortunately, having the Long-Range Scanners augment you can see the storms from afar and avoid them accordingly.
Boarding drones. They're essentially Rockmen boarders but with the attack power of a Mantis and an immunity to suffocation. They pass through shields and cause a hull breach in the section they impact, making it that much harder to kill them if they're attacking a system. Oh, and if you manage to kill one, the enemy will just send another, which will put another breach into your ship, unless you take out their drone control first or they run out of drone parts. If you get hit by one, hope it doesn't land anywhere vital and destroy the enemy's drone control before it causes too much damage. While they can be intercepted by defense drones, they're small, fly fast, and can be launched faster than missiles, and have a better chance of getting by as a result. Zoltan Shields and cloaking can buy you some time to try and take out enemy drone control, if you have them, and Slug ships can automatically repair breaches, making them slightly less hazardous.
Most of the time, Rebel AI-controlled Auto-Scouts and Auto-Assaults are Goddamned Bats. However, ships that lack direct damage weapons will find themselves largely incapable of doing anything about these ships. The Mantis B can defeat Auto-Scouts by launching a Boarding Drone at them and letting it destroy and re-destroy systems while the Auto-Scout auto-repairs them, but this doesn't work against Auto-Assaults because they're compartmentalized and hence prevent the Boarding Drone from moving around within them, requiring a very tedious and specialized method to destroy them without weapons. The Unidentified Cruiser Type B can't destroy either until you find some regular weapons. And, to provide a challenge for any and all ships, sometimes in the late-game you can run into really dangerous Auto-Assaults, packing defense or anti-ship drones, cloaks, full batteries of four weapons, stupidly high evasion, and (rarely) up to five layers of shields. And since they're automated and depressurized, they can't be damaged by fire and have no crew that can be eliminated, so you're in for a long hard slog to try and bring them down.
If you're in a Slug nebula, then expect to run into many events where a Slug ship hacks your oxygen/medbay/doors/engines/various other systems, and then exploits your newfound weakness. If you haven't upgraded your systems enough to get a blue option, then you're in for a world of pain. Particularly nightmarish are the ones where they hit your oxygen, since that essentially puts you on a strict timer to either kill the ship or bail.
Any enemy ship with a medbay for the Mantis B, a boarding-oriented ship that don't start with any weapons. Enemy crew will simply retreat to the medbay at low health, and fighting in the medbay is pointless since the enemy can simply heal faster than you can damage them. Unless you've managed to pick weapons capable of hitting the medbay, or use a Boarding Drone to create a distraction while your crew chips away at the medbay (and even then there's no guarantee the distraction will work) you're better off escaping. The Crystal B ship is also boarding-oriented with no weapons, but at least Crystals can lock down rooms to prevent enemy crew from getting to the medbay.
Missiles until you get Drone Control and a Defense Drone. Because they penetrate shields, missiles over time can add up to costly amounts of hull damage, to say nothing of having your systems crippled. Whoops, your weapons just got hit, time to run...excpet you can't, your engines just got busted too...and now you're dead before you even left the second sector.
The ships in the Crystal Home Sector. They tend to show up with full arsenals of crystal weapons, which ignore one layer of shielding. Even worse, Crystals are very tough to kill, having boosted health and being resistant to suffocation. They can easily put a serious crimp in your plans to complete That One Sidequest.
The Weapon Pre-Igniter. Being able to open fire the moment a fight starts typically lets you crush any opponent who isn't completely immune to your arsenal. Even the final boss is a lot easier to beat thanks to being able to shut down some its more powerful abilities on the spot. There's an achievement for destroying an opponent outright with this ability.
Laser Spam. If you can manage to get more enough burst laser weapons on a single ship, you can totally overwhelm any defense. Barring unlucky misses, one barrage is often enough to significantly damage or cripple a system, as long as you use an Alpha Strike. No need for strategy or tactics, just target their weapons to take them out of the fight, then either blow them up or board and kill the crew. Combine with either a cloaking device or the aforementioned pre-igniter, and even the flagship will go down in short order. The highest level of Burst Laser shoots 5 lasers, enough to defeat any shielding system bar a handful of extremely rare 5 shield ships. You can take out pretty much any ship in the game with just this weapon alone.
Variations on this strategy include throwing in a Heavy Laser II, which fires two 2-damage lasers that have a good chance of causing a hull breach, draining oxygen from a room and forcing enemy crew to repair it (especially if the room is a system room; hull breaches have higher repair priority than the systems themselves), or a Hull Laser II, which fires three shots that do double damage to empty rooms, for a potential total of six points of damage. Should a crew member or four happen to be inside the attacked room, a few of these high-damage lasers will render them dead very quickly. Combine these with two or three Burst Laser II's, and you can quickly grind the Rebel Flagship into dust.
The Fire Beam. It doesn't do any physical damage, but one well-aimed shot can spread five or six fires across two or three rooms. If you're not against a crew of Rockmen, that's almost guaranteed to overwhelm any attempt the crew makes to extinguish it, and even Rockmen will have trouble with that much fire. Killing the crew without destroying the ship is trivialized, allowing you to collect increased scrap harvests. The only downside is that any ship with upgraded doors kills its usefulness. Also, if e enemy ship has even one layer of shield, it's useless unless that shield is disabled or destroyed.
The Rock Cruiser Type B, or "Shivan". Its Heavy Pierce Laser can dominate early sectors before the enemies get over one layer of shielding, seeing as it charges fairly fast, ignores one layer of shielding, and cannot be otherwise blocked except by evasion. And it does as much damage as an Artemis missile, but without using ammo or being vulnerable to Defense Drone Mk. I's. And while it's true that it becomes ineffective by itself later on, it gives you an advantage long enough to acquire either more weaponry or a teleporter and some supporting crew. If you can free up two of your (four starting) Rockmen to become a boarding party and use Fire Bombs (which you also start with) before you teleport in, you can quickly and permanently disable any enemy system of your choice - usually weapons, shields, or medbay. The fire begins spreading and damaging enemy systems, while the Rocks prevent the enemy from putting them out, and both the flames and combat quickly deplete enemy crew health. The enemy crew will generally flee the burning room as soon as they realize they cannot survive staying there, giving your somewhat damaged Rocks a safe haven while also knocking out an enemy system hard. After that you can teleport out, heal and repeat, or else just finish off the enemy crew if you still have the HP or have reinforcements beaming in. Often the increased rewards from boarding as opposed to destroying ships allow for a very smooth game, helped by the fact that you can ignore the increasingly strong enemy shielding in later sectors, overwhelm and burn down their medbays, and build up the defenses on your own ship to create an extreme tank. And you still maintain the direct firepower to strip Zoltan shields when encountered, and if you're careful, you can even board depressurized auto-assault ships as needed - Rocks have the HP to last until your teleporter recharges, as long you make sure they don't get stranded there during a cloak activation.
The drawbacks: you need to unlock the Rock Cruiser Type A first and then use it to get two of three dastardly achievements, although one of those achievements also unlocks another equally powerful ship (see That One Sidequest below). And you have no doors, and no airlocks, so your slow-moving Rocks have to deal with fires and enemy boarders personally.
The Crystal people. Their ability to lock down a room, preventing anyone from entering or leaving makes whoever you are facing in the room outnumbered, outgunned and unable to escape, ensuring a certain death. Combined with their extra HP and tolerable speed, and you have the ultimate boarding crew. Their Type B ship takes this even further, with a four-capacity teleporter right next to a medbay, and you start with three crew. Their Type A ship is no slouch, either, possessing weapons that bypass one layer of shielding and don't require ammo, though you can't find more of said weapons.
The Mantis Cruiser Type B "Basilisk", with its starting 4-man teleporter, boarding drone and level 2 shields. It doesn't come with weapons, but you do not need them. There is only one type of ship it cannot beat outright, and that's easy to fix once you've got some scrap to upgrade your teleporter one level. Almost every encounter can be won simply by beaming over your entire crew to kill off the opposition while your shields soak up any damage they can do. This also gains a lot more scrap than blowing ships up, making it much easier to improve the ship. For AI ships, you can use your boarding drone to destroy systems slowly (AI-Scout) or a combination of the level 2 teleport and drone (AI-Assault). With all that extra scrap, you can easily buy weapons to disable ships you can't kill by boarding. By far, this ship is the easiest one to get to the endgame with because it affords a considerable early game advantage.
Breach Bomb II, which tends to wreck entire ships in one well-placed burst if it hits. Because it does damage to crew members and opens holes in the ship, this can be used over and over to disable most any ship save for Slug ships without destroying it. This even works on the Flagship; repeatedly applying the Breach Bomb to the medbay in the first stage can lead to the entire crew dying painfully, leaving it open for a boarding party to disable during the other stages. Finally, AI drones and the Flagship's last-resort AI don't repair breaches, and breaches in system rooms need to be repaired before any system damage can be repaired, so any system damage in a breached room will never get repaired, leaving them permanently disabled (unless you jump away and then come back later).
Ion Bomb. 4 ion damage? Check. Bypass defense drone? Check. Only take one energy bar to keep it active? Double check! Some ships can easily win the game with its starting weapons if it manages to find an ion bomb, and stock up missiles for the bomb itself.
In nebula sectors, Long-Range Scanners. No more of those pesky ion storms! (Unless the randomly-generated beacon setup forces you to go through one, but even then you'll be at least forewarned about it.)
Ion Blast II combined with one or more Ion Blast I. It only takes a few quick salvoes to take down even level 4 shields, after which you can keep two or more systems more-or-less constantly disabled, then just relax and take your time finishing off the enemy. Especially good in combination with beam weapons, or with teleported crew.
AI Controlled Scouts when using the Mantis Cruiser B. No weapons, you have to send over a boarding drone to very slowly blow up each of the ships systems, wait until they repair a few times, and then finally the drone will blow up the ship for measly scrap, often less than 10 value on Normal.
Auto-Scouts in later sectors tend to have stupidly high evasion. Coupled with multiple layers of shielding, firing a volley of 8 shots and still failing to land a shot is not unheard of.
Slugs in general, with their system-disabling shenanigans. Add in that they live in nebulas, which people already tend to avoid for their sensor-disabling annoyances and the aforementioned plasma storms, and you get one really annoying race to deal with.
Ion weapons, especially either Ion Blasts or Ion Bombs.
Cloak tends to prolong most battles it's in. Usually, the only dangerous enemy that has cloak is the Flagship. Most of the other times, all it does is waste your time.
Zoltan ships with Zoltan Shields, if you do have weapons, primarily due to the extra time needed to eat through them.
The fact that many elements of the game are random does not sit well with some players. Case in point: In one run, you may end up finding four Burst Laser II's, allowing you to cheese the Final Boss with 12-shot laser spam. In another run, you may be stuck with default weaponry or at the least ineffective weapons at stores that prevent you from damaging the flagship at all unless you also invest in a teleporter.
One particularly crazy one involves using absolutely no oxygen on your ship at all. You'd think everyone would quickly die from asphyxiation, but apparently a level 2 Medbay completely nullifies the damage taken from asphyxiation. It's still ridiculously difficult, since the Medbay is only so big, and you need someone at the helm to jump the ship from point to point. It's been done, however crazy it sounds.
Some people think that Engi Cruiser B or Stealth Cruiser B are also "hard-mode" ships. Engi B has a single crewman, no sensors, and has drones take care of boarders and ship repair. Stealth B has no shields and starts with only one weapon: the incredibly slow-charging but powerful Glaive Beam.
Ancestry, which requires you to go through That One Sidequest in the Rock Cruiser. That said the Rock Cruiser has blue options that make it slightly easier to complete. If you intend to do it in the Type A, get non-missile weapons as soon as possible (see Demonic Spiders above). If you intend to use the Type B, you need to complete two other hard (but still much-easier-than-this-one) achievements in the Type A to gain access to it - which involved destroying an enemy ship which has a defense drone using only missiles (alright, you start with only missiles, but defense drones are... designed to block them, and ships that field them often have the crew or repair drones to keep their drone control online), and killing an enemy crew in a room which is on fire (which is hard because you need to set a room on fire, then board it and kill an enemy crew member there - and the enemy crew members are programmed to flee from burning rooms if they can).
Missiles in general are much hated by just about everyone without a defense drone. It's not that they're powerful (early on they do one or two damage a pop), it's that they pass through shields. Worse still, they charge fast enough that you can pretty much guarantee the enemy will fire at least one before you stop them. Especially in the early game, this hurts a LOT over time. Later in the game, enemies can field larger missiles that do as much as four damage per hit, but they mercifully take longer to charge and you'll probably have a defense drone by then, as well as high evasion and possibly a cloaking system to help avoid them.
The flagship's triple missile launcher is notorious for this reason. At best, a defense drone of any make can take down two missiles, and while you can cloak to dodge them, this only works every other time due to the longer cloak recharge. Unless you're fast with your teleporter, odds are a missile is going to connect. On the final stage, it's practically a guarantee since the Zoltan shield takes so long to get through.
The flagship's first power surge, the drone swarm, is possibly the single most damaging attack in the game. If your shields go down for even a second, you WILL be feeling the pain. It's not an exaggeration to state that if this pierces your defenses and takes out a vital system (like shields), you will probably lose. It also has a tendency to sync with the triple heavy lasers connecting with your shields or the triple Leto missiles firing. You'd better pray that their Halberd Beam isn't also up.
The flagship's bigger attacks practically make it mandatory to have an evasion stat over 50% (and/or a cloaking device) which you can never, ever let go offline, because you will die if your evasion is turned off. You also better hope the boarding drones in the second stage land somewhere other than your cockpit, or that your defense drone can shoot them down repeatedly until the flagship's supply runs out.
Shieldless ships. Only three ships don't start with laser and beam-repelling shield systems and while they have alternatives (a cloaking system in two cases and a special single-use shield in the third) they can be rapidly picked apart by anything with a beam drone (attack drones fire constantly for low damage which shields would normally absorb, but which adds up, and beams can't be dodged).
The "Unidentified Cruiser" is a Game Breaker for a reason. Many players take dozens of attempts before they get a run that gets the very specific, luck-based order of sectors that allows the sidequest to be finished.
To a lesser extent, unlocking the Rock Cruiser Type B, which requires completing two out of three Rock Cruiser achievements:
The Ancestry achievement is the same thing as hunting down the Crystal sector, minus acquiring the Crystal Cruiser.
At the least, the Defense Drones achievement is simple—just find a Rebel Rigger with a Defense Drone and then use missileAlpha Strikes to prevent the Defense Drone from being able to shoot both missiles.
The "Is it warm in here?" achievement requires killing a crew member of an enemy ship in a burning room, which is not easy because this requires a Teleporter and a way to start fires. Most weapons only have a low chance at best, and it's not uncommon to never find the Fire Beam or Fire Bomb, and even then Fire Bombs use missiles and can miss, while the Fire Beam requires that the enemy ship's shields be down first. Oh, and enemy crews retreat from burning rooms at low health, requiring you to time your attacks correctly so they get their last points of health beaten down before they can escape the room. And finally, the crew member must die from one of your hits; if the fire whittles them down to 0 HP, it doesn't count! You can guarantee this achievement by getting to the Rebel Flagship with a Fire Bomb in tow and using it on one of the weapon rooms, but it still takes a bit of a while to get there.
The Slug B ship, The Stormwalker, which is a boarding-oriented ship. The catch? It has no starting medbay, and all three of its starting crew are Slugs, which are average boarders at best. The idea is to use Healing Bursts to recover your Slugs so they can keep fighting, but Healing Bursts use missiles, happen to be your only means of recovery (which means post-battle recovery will consist of wasting another missile), if your Burst misses you will have to beam your boarding team out, and if your missiles run out, you're screwed. Early game tactics involve making a mad dash for the nearest store so you can purchase a Medbay, which costs 60 scrap.
The Engi B ship, the Vortex, starts with one Engi crew member, and its weapons consist of a Heavy Ion and a Heavy Laser. You can depressurize every room except the cockpit to stop fires and hold off boarders (especially in conjunction with your Anti-Personnel Drone), but if you get boarded in the cockpit (especially if the boarders happen to be Mantis), you are in a lot of trouble, as Engis have halved combat damage and leaving the cockpit will drop your evasion to 0% unless you have the cockpit upgraded to have an autopilot, and even then your evasion will remain nearly nonexistent unless your engines are maxed out. As for the weapons, the Heavy Ion takes a long time to charge, and if it misses, you won't be able to use your Heavy Laser on anything unless you're up against an unshielded Auto-Scout or are in an asteroid field with a one-shield ship. The slow recharge rate of the Heavy Ion also means that if you don't find another gun to help supplement it, you're basically dead when you start facing enemies with 2 shield blocks, since even with maxed out gunnery skill, the ion damage on shield will dissipate before another ion shot hits.
The Stealth B ship, DA-SR 12. Like the Stealth A ship, it starts with a cloaking device, but the shield system must be purchased separately for 150 scrap. Its main differences are that it has only level 2 engines instead of level 4, has level 2 cloaking, and its only weapon is the Glaive Beam, a beam that does 3 damage per room, but takes 25 seconds to charge (about 23 if you have a zero-level gunner) and uses 4 bars of energy. Even the Federation Cruisers' Artillery Beam fires faster when maxed out. If your weapons and/or your cloaking get hit in the early game, your best choice is simply to restart.
As far as crew examples go, humans. They trigger no blue events, have no special abilities, and are only effective in combat when against Zoltans or Engi. Slugs have the same stats as humans, but also have telepathy and can trigger blue events.