History YMMV / Subnautica

** Lava Larvae. These volcanic leeches stick to your vehicles and drain their power. This isn't a big issue for a Prawn, which only has so much room for them, but they will swarm over your Cyclops like it's a free meal, and enough of them can easily outpace a thermal charging upgrade. There are numerous ways to remove them directly (Repulsion Cannon, knife, Cyclops shield, grav spheres), but all of them require diverting your attention. More importantly, Lava Larvae will swarm regardless of whether or not you are present, so if you leave for some other task, you may come back to find a dozen of the little monsters have taken up residence on the hull and sapped a fair bit of power. Another more obtuse trick is to deliberately pull your power cells before you leave and store them in a locker. If there's no power, the larvae won't attach, and you can plug them back in later.

* AssPull: As part of the course of the story, another ship, the ''Subbeam'', will detect the ''Aurora'' distress beacon and attempt to render aid. This results in [[spoiler:the planet's automated defences vaporizing the ship for violating the quarantine]]. If SequenceBreaking is used to [[spoiler:disable the quarantine platform]] before their arrival, they will instead refuse to land, citing the thick layer of debris orbiting the planet, even though it doesn't impede their approach should you let events play out normally.

* AssPull: As part of the course of the story, another ship, the ''Subbeam'', will detect the ''Aurora'' distress beacon and attempt to render aid. This results in [[spoiler:the planet's automated defenses vaporizing the ship for violating the quarantine]]. If SequenceBreaking is used to [[spoiler:disable the quarantine platform]] prior to their arrival, they will instead refuse to land, citing the thick layer of debris orbiting the planet, even though it doesn't impede their approach should you let events play out normally.

** Players will almost always build their first base in the Safe Shallows due to being [[CaptainObvious one of the safest biomes in the game]] roughly at the center of the world map, and therefore closer to most biomes around so they can go gather resources without having to travel too far away. There's even a nice open spot in the Grassy Plateaus about 200m from Lifepod 5, right near an entrance to the Jellyshroom Caves, seemingly encouraging players to take advantage of it.

* CreepyAwesome: The leviathans are some of the most iconic characters of the games. While the hostile ones can be absolutely horrifying both during the day and especially at night, a lot of players find them really cool and jaw-dropping.

** The Stasis Rifle and Thermal Knife can kill anything in the game without the player taking a single point of damage. The only drawback is the amount of time the leviathans take to kill; any other target will die in one uncharged stasis shot and just a few hits with the knife. This turns even the dreaded Reapers into tempting targets, [[MundaneUtility or even just makes them easy to scan without threat of being attacked]]. This is explicitly mentioned by the devs as the reason the stasis rifle was removed from ''Below Zero''.
** While only unlocked a fair way through the midgame, Thermal Generators can completely eliminate practically all seabase power management concerns. A cluster of them built near or especially within hydrothermal vents, black smokers or the game's deepest volcanic biomes will constantly generate power at a rapid pace, with no further maintenance or resource consumption required following initial construction. Any concerns regarding vent proximities to ideal/desired seabase sites are largely addressed by Power Transmitters, which only a few are needed to carry power across generous distances, even doing so ''through terrain'' when connecting to neighbouring transmitters/seabases.

** Stalkers. Once the initial fear meeting them subsides, they become simple pests that have a surprisingly far-roaming distance due to tracking down metal salvage. While they aren't terribly dangerous, they will nip at you and your vehicles if the opportunity arises. What really makes them annoying, however, is their '''obsession''' with camera drones. If you build a Scanner Room anywhere near a Stalker, it is a guarantee they will go out of their way to pull camera drones out of their sockets to play with them.

** Lava Larvae. These volcanic leeches stick to your vehicles and drain their power. This isn't a big issue for a Prawn, which only has so much room for them, but they will swarm over your Cyclops like it's a free meal, and enough of them can easily outpace a thermal charging upgrade. There are numerous ways to remove them directly (Repulsion Cannon, knife, Cyclops shield, grav spheres), but all of them require diverting your attention. More importantly, Lava Larvae will swarm regardless of whether or not you are present, so if you leave for some other task, you may come back to find a dozen of the little monsters have taken up residence on the hull and sapped a fair bit of power. Another, more obtuse trick is to deliberately pull your power cells before you leave and store them in a locker. If there's no power, the larvae won't attach, and you can plug them back in later.
** Lava Lizards are like underground Stalkers: not terribly dangerous, but quite aggressive. What makes them worse than Stalkers is that, instead of targeting mundane things, these lizards absolutely ''hate'' your Prawn, and will attack it without end, even if you're not in it. It's very easy to lose a Prawn to them if you're not paying attention.

** As of the press release right before exiting Early Access (version 1.0), players can interact with Cuddlefish ''through walls''. A Cuddlefish roaming outside can thus be pulled into a base (where they fly around as if they were in water) or even pulled back into their containment tank.
** Since early access and extending into 1.0, there's an infamous bug that lets small fish clip through the base. Don't be too surprised at seeing a school of fish fly through your base, or a single curious Peeper floating through your hallways. Some players love to HandWave it as the player character hallucinating and [[GoMadFromTheIsolation going mad from solitude]] and being marooned on an water-filled alien planet. On the other hand, this becomes annoying since fish in containment can clip out of their tanks and start roaming the base (or, worse, clip outside the base into the wild).

* ObviousBeta: Even with the rest of the game functioning fine, the ''Aurora'' remains are blatantly this. It's full of a bunch of arbitrary invisible walls that make traversing it more of a maze than it already is, and it has a number of textures that you can just swim right through.

** The mechanics behind powering seabases are odd, to say the least, and the game doesn't bother explaining it beyond what's visually obvious. Your seabase will display the total amount of reserve power available, representing the sum total of your individual generators. What the game doesn't tell you is that it will draw from each one in sequence based on the order they were built, rather than spreading the load during times of high stress. You can have several different types of generators running, but the game is always going to take from the one built first, even if it wastes resources (for example, drawing from a Bioreactor when Thermal Plants are running). You thus have to carefully set up your power generation so the resource-intensive ones get tapped last, or simply run only one type so you use them consistently (Thermal Generators, for example. See GameBreaker above).
** So are the mechanics behind base integrity. The concept itself is fairly straightforward: structural elements provide bonuses/penalties to your base integrity, and if integrity drops too low, the hull is breached and you have to reinforce/repair your base. The problem is that the game never tells you what the bonus/penalty values are. Descriptions will occasionally note if a component will add or detract from integrity, but only in extremely obvious cases. The current level of integrity also only appears when parts are added or removed, so if you didn't have a safe margin (and the reinforced panels that grant integrity bonuses are rather expensive at early stages), better grab your repair tool and go waddle around your flooded base hunting them breaches! In addition, the penalties increase the deeper you descend, which could lead to an absurd situation where even building just the room and the hatch will be enough to flood it. Finally, the game sums the integrity effects of all elements that are ''adjacent'' to one another, not just those that are actually connected, which just makes no sense.

* SelfImposedChallenge: Wiping out the hostile leviathans is one for many players. There are only so many of them (22 reapers, 6 ghosts, and 3 dragons), and once they're dead they're gone for good so killing them is not only a challenge, it also makes the Crater much safer to travel.

* SpiritualAdaptation: A space traveler stranded on an hostile planet, and trying to survive using the technology at his disposal? That sounds like ''[[Literature/TheMartian The]] [[Film/TheMartian Martian]]'', set underwater.

* ContestedSequel: While reception to ''Below Zero''[='=]s new biomes and creatures is mostly positive, the story and gameplay have proven divisive. Many players found the story engaging and enjoyed the increased character interactions (including the new player character having her own personality and goals rather than being another HeroicMime). Others feel that these elements detract from the [[SpaceIsolationHorror isolation]] that made the original game so terrifying, and also complain about ''Below Zero'''s [[ItsShortSoItSucks shorter length]] and [[ItsEasySoItSucks more relaxed difficulty]].
* DesignatedHero: Sam Ayou is supposed to be seen as heroic for her [[spoiler:trying to stop Alterra from researching the Kharaa, but there's just so little evidence that something bad might have actually happened that it makes Sam come off as paranoid. Not made better by the fact that that her trying to prevent further research caused the death of a man with family]].

** In ''Below Zero'', if you keep a Flare on hand while on land, you needn't fear Snow Stalkers ever again as they will be afraid to attack you while you're holding it. This makes the surface portions of the game significantly easier, especially since the Flares won't burn out unless you throw them.
** The humble Spicy Fruit Salad. Though one of the ingredients can't be accessed until a certain point in the plot, once it is acquired all semblance of difficulty pertaining to hunger management vanishes. Spicy Fruit Salads restore more hunger than a nutrient bar, more water than filtered water, fully restore the temperature gauge, are nonperishable, and ''take up one inventory slot''. And since both of the ingredients can be grown indoors, you can manufacture enough food for an entire playthrough within ten minutes.

** The Chelicerate effectively replaces the Reaper Leviathan as the biggest and nastiest fish you'll encounter near the surface. However, while its attacks rival the Reaper in strength, it is much less aggressive and its general "oversized shrimp" appearance cause it to lack the Reapers' scare factor, so it's generally seen as an inferior replacement for the original game's iconic super-predator.
** The Sea Truck is a massive downgrade from the Cyclops submarine of the original ''Subnautica''. The Cyclops could be modified with the Fabrication tool, allowing the player to turn it into a mobile base with enough food, water, and item storage for days of exploration. The Sea Truck, by comparison, is essentially a Seamoth with the ability to add dedicated modules which are in every way inferior to what the Cyclops can offer, with the only caveat being that the Sea Truck is faster and draws very little power.

* SequelDifficultyDrop: ''Below Zero'' on the whole is a fair bit more forgiving than the first game. The map is smaller, there are less predators to deal with, and there are less vehicles to manage so progression moves along at a faster pace. While the risk of freezing on the surface provides an added challenge, it's easily mitigated and generally isn't likely to happen unless you're careless.

** Earlier in ''Below Zero'''s development, Robin was voiced by an actress with a British accent, in the final release, she has an American accent instead. Some players, notably WebVideo/JackSepticEye, regrets the former voice because they think having a character with a non-American accent was unique and refreshing.

* ToughActToFollow: Regardless of how one feels about ''Below Zero'', it's widely agreed that the first game's story, environment, and gameplay mechanics set the bar incredibly high, and that it would be very difficult for any sequel to live up to it.

* GeniusBonus: The fauna on 4546B has some thought put into it. For example, Reaper Leviathans are the primary Apex Predator of the above-cave-level places on the planet, and as such they are one of the few animals in the entire game that lack any kind of bioluminescence, which means they can very easily sneak up on you.

** Cave Crawlers. They don't deal that much damage and are easy to walk around and avoid but are still annoying to deal with on land since they jump all over the place, making it harder to slice them up with your knife.

* NightmareRetardant: While the Sea Dragon Leviathan is menacing on paper, that doesn't stop its slow speed and general "mermaid" aesthetic from coming off just a bit less scary than it ought to be.

* ScrappyMechanic:
** The Snowfox handles more like a rusty shopping cart than a badass speeder bike, and while it is fast in a straight line, it just isn't well suited for navigating the narrow caves and winding paths that make up the land portions of the game. Many players instead opt to [[NotTheIntendedUse carry it around in their inventory as a portable heat source]]. It's much easier to build a Prawn for the same task, making yourself pretty much unkillable, albeit much slower.
** The Moonpool is unchanged from the first game, with no accomodations made for Sea Truck modules. As such, until you obtain the dedicated Sea Truck Dock module, you'll need to detach your modules every time you dock the Truck and reattach them every time you launch.