After seven hours in early access, Subnautica 2 feels more like a remake than a sea-quel, but it has plenty of room to grow

New ocean, same kettle of fish

Like the original Subnautica, released into early access an unnecessarily long time ago in 2014, Subnautica 2 pumps fresh life into the often-grindy survival genre by depriving it of air. Out in early access today, it's a familiar but engrossing meditation on ocean exploration, with a backstory that inclines towards the abyssal dread of SOMA. You begin the game as a crash-landed space colonist, downloaded into a 3D-printed body by "Noa", a softly overbearing corporate AI. Your goal as Noa's "Qualified Investigator" is to work out why your ship crashed, and what happened to all the other colonists Noa revived before you.

You have 45 seconds of air to work with, at first. That's enough to get you down to the seabed near your floating lifepod, where you can scrounge a few reproachful slugs to convert into potable water, and rip some titanium chunks from the sand. You might also peek into a cave. There's always something intriguing at the bottom of a cave in Subnautica 2 – a rusty gadget you can scan for a crafting recipe, perhaps, or a lurid growth that might supply ingredients for that recipe. But you've only got 20 seconds left in your lungs, which surely isn't enough time to make it all the way there and back. You try it anyway, and suffocate like an idiot... and wake up in a newly printed body, devoid of inventory save the equipment in your tool bar.

The rhythm of diving and surfacing forms a risk-reward loop comparable to Halo's infamous '30 seconds of fun, over and over', with the obvious difference that Subnautica 2 skews pacifist – you'll acquire ways of defending yourself, but you're never a hunter. The loop sets the game apart from survival sims that impose less tangible constraints, like ordering you to be home by sundown or, worse, imposing level requirements on areas. Subnautica 2 does this a little, in fairness, with maximum depth constraints for vehicles, and protective gear needed for certain regions, but all of that comes second to the question of lung capacity.

As the opening hours pass, you grow expert at operating within that loop, feeling out the distances and how the whimsical undersea terrain may support or punish curiosity. Some of those caves contain air pockets, or forgotten habitats that still have power, or fluting, big-bellied plants that burp oxygen at regular intervals. Subnautica 2 also introduces fixed sea currents - extremely videogamey rollercoasters into and out of the crevices. They can be shortcuts between resource deposits, or ways of accessing the deeper caves, or absolute deathtraps. Often, it's all three. You'll never know, until you go with the flow.

The loop gradually widens, as you haul a variety of rocks and protesting pondlife back to your fabricator in the pod. You'll craft bigger air cylinders and mobility aids, like the new wrist-mounted waveracers - an osteopath's nightmare, as the codex acknowledges, but very convenient when the hideous directional audio alerts you to a charging leviathan. And you'll equip "biomod" buffs at medical stations, one of Subnautica 2's new supporting mechanics. My favourite biomod so far lowers your air consumption drastically while you're stationary, allowing for more relaxed scrutiny of smashed bases and their emergent tales of woe.

The first biomods are found in one of those wrecked facilities; eventually, you'll get to build your own seafloor hubs decked with solar panels and wave generators, steadily producing oxygen while the electricity is flowing. Still, however clever your technologies and however piscine your flesh becomes, there is always the thrill of knowing that at some point, you need to surface. Every Subnautica 2 expedition is a countdown to asphyxiation. It's what makes them such fun.

The water itself is a glamorous, undulating beast, its colour and composition altering by the fathom. The shallows cultivate a party atmosphere, all smeary sunlight and salvos of neon fish. Head to the very edge of the starting reef, and the brine condenses to a forbidding, dusky purple, thick enough to camouflage even the largest predator. It's really lovely water. Is it lovelier water than you'd find in Subnautica 1? In some pixel-counting technical sense, yes, absolutely: this is the era of Unreal Engine 5 and all of its crazy hyperrealist bullshit. The world feels more 'lifelike', as well - the creatures more autonomous, responding both to the player and each other. There's a kind of grumpy parrotfish that loves headbutting the massive crabs that gather near sulphur pits, flaring its crest in a way that reminds me dimly of the Thwomp blocks in Super Mario Bros 3.

Still, I can't say the overall ambience is very different, so far. In general, Subnautica 2 risks being too similar to Subnautica 1. The initial biome is broadly a revamping of the first game's opening coral reef. There are weirder environments to discover further down with the aid of a sonic cannon - catacombs where some viral entity has taken hold, and the water is as appealing as week-old gravy - but I occasionally struggle to tell screenshots of each game apart. It feels like the environment designers have snapped back too hard from the mildly divisive Subnautica: Below Zero, released in 2019, and are fervently playing the hits. We'll see what the other biomes add over the course of early access.

For many returning players, that closeness will be a relief, and this is just the opening area. Below Zero copped a lot of flak for having a voiced protagonist; in Subnautica 2, the only time you'll ever hear a player character talk is in co-op multiplayer, which I haven't tried yet due to a combination of my usual acute misanthropy and not having enough Steam codes. Your AI overlord Noa has plenty to say, but you'll only ever talk to him at terminals; there's no robo-dialling your earpiece while out on manoeuvres.

The sheer coherence of Subnautica 2's early access build is also slightly miraculous, given that the developers have spent the past year in legal hell. I encountered no technical problems of note, and the distribution of resources and crafting recipes seems well judged, with codex hints and environmental cues guiding you towards rarer materials. Still, after seven hours, I do feel like I'm playing a remake rather than a sequel.

Many of the differences I noticed are smaller, quality of life questions. Base-building is a lot more malleable, for example. It's the same system of placing and painting holographic templates, but you can stretch and reshape your windows, moonpools and so on using a context-sensitive brush. The first vehicle you'll build, the Tadpole, is similarly flexible, with hard points for optional turbowings, storage lockers and the like. I miss my old Seamoth, but I do love the Tadpole. It's like one of those clip-together toylines with a treacherously low-priced base edition. I'm looking forward to growing it into a Frog, assuming that's the trajectory here.

More than that, though, I'm looking forward to unravelling the game's plot and backstory, which continues the original's theme of corporate pioneers slowly becoming part of a wondrous and noxious alien ecosystem, but features a larger background cast and more of a fallen human society to discover.

Lore docs form a conversation between ideologies, ranging from defiant humanism to post-anthropocentric mysticism. There's an audiolog in which one woman muses on interspecies solidarity based on her experience nurturing sponges that produce antibiotics. "Nature isn't just red in tooth and claw," she says. "There's more going on than a market of violence." (That's a crafting recipe in disguise, of course; there's still an exchange economy in play here, if not a market of violence.) Other colonists have found religion of a kind. They dream of a "jubilee" that will wash away their debts, corporate and otherwise - a rapture linked to the huge treelike organism on the horizon, which draws people magnetically towards it.

Another point of overlap with the first game is that the ocean's microbes are slowly killing you, with no remedy available. Noa's blithe solution is that you die regularly and keep switching bodies. Noa himself is a transferable, segmented consciousness, a "cephalopod-inspired architecture", made up of a central executive and autonomous limbs. In visiting the collapsed habitats of bygone explorers and turning the power back on, you are joining up the legs of the octopus, which lends the ritual of 'unfogging the map' a sinister edge.

What will be the outcome of exposing your Noa to the subordinate Noas along the periphery, including the ones that have seemingly gone a bit loopy? It seems important, in this context, that your own personal AI can't stop "reminding" you of your relationships with the people it wants you to locate. It is oddly insistent that you feel a personal bond.

Subnautica 2, then! Good game so far, I reckon. Nice coral. Pleasantly invasive mood of posthumanist disarray. I particularly enjoyed the bit where I got lost in one of those tunnels, blundered through clouds of acid emitted by some very anti-social tubers, snagged on some barnacles and died about three feet from an air pocket. Ollie is further ahead than I, and he reports that there's a giant clam out there that harbours a lot of lithium. I look forward to souping up my Tadpole with robot boxing mitts and paying that clam a visit.