You play as Non-Essential Systems Maintenace Chief Ryley Robinson and begin the game in an underwater Lifepod 5 in a watery alien world . The vessel contains everything you need to stay alive, this includes two nutrient blocks, two filtered waters, and two flares. There is also a food and water meter, an oxygen meter and a health bar. Early in the game you will be able to craft a survival knife using the Fabricator which can be used to defend yourself against predators and procure samples of certain flora and corals, such as Creepvine Samples and Coral Samples.
If you die for whatever reason you will respawn back in your Lifepod 5 having lost some of your items. There is also a radio in Lifepod 5 which once you manage to repair will get the game's plot rolling. There are various different biomes to explore and each of them will have its own ecology of resources and angry sea creatures to fend off. Once you have found a habitat you like you can begin building a Seabase which is an area where you can return for oxygen, and serves as an alternative to Lifepod 5 as a base of operations.