Subnautica: Below Zero

Subnautica: Below Zero is a survival adventure game set in an underwater open world environment and played from a first-person perspective. The player controls xenologist Robin Ayou, who lands on ocean planet 4546B in pursuit of answers about her sister Sam's mysterious death. Like its predecessor, gameplay involves exploring and surviving in alien environments while also completing objectives to advance the game's plot. Players collect resources, construct tools, build bases and submersibles, and interact with the planet's wildlife.

To survive and progress, the player must collect raw materials from the environment, including various minerals, flora samples, and fish, while avoiding or countering threats like hostile fauna and blinding snowstorms. They must also acquire blueprints to craft new items, either through finding and opening databoxes in the world or by scanning fragments of the item. Generally, the player must face harsher environments the further they progress, requiring better equipment or upgrades for old ones, like suits that resist the cold, oxygen tanks with higher capacities, or vehicles that can withstand deeper waters.

Two years after the events of the original game, the Alterra corporation that originally crashed the Aurora on planet 4546B had built several bases on the planet for research on the Kharaa bacterium, and on the alien precursor race, dubbed Architects, that had studied the bacterium prior. Xenologist Robin Ayou smuggles herself onto the planet in a frozen sector named "Sector Zero" to investigate the circumstances of her sister Sam's death, which Alterra claims was a result of "employee negligence." During the past year, Alterra had recently withdrawn all of its personnel, allowing Robin to land on the planet.

Shortly after landing, Robin picks up a distress signal and goes to investigate it, discovering an alien sanctuary containing the digitized consciousness of a living Architect. Desperate for a new storage medium as the sanctuary's power is running out, and after an apparent misunderstanding, the Architect downloads itself into Robin's brain. Angry at it for intruding into her mind, Robin initially tries to ignore it, but soon agrees to help it, now introduced as Al-An, to construct a new body to transfer into. To do so, Robin combs the sector for alien installations and artifacts to find the necessary components and materials.

Subnautica: Below Zero was initially envisioned as a downloadable content (DLC) pack for the original Subnautica (2018), though its scope eventually expanded significantly, prompting Unknown Worlds to release Below Zero as a standalone product. It was initially considered to be a sequel to Subnautica, but with the announcement of the third game in the series having the title Subnautica 2, the game is now considered to be a spin-off. Announced in August 2018, Below Zero was released into early access for macOS and Windows on January 30, 2019. The full game was released for these platforms, along with versions for Nintendo Switch, PlayStation 4, PlayStation 5, Xbox One, and Xbox Series X/S, on May 14, 2021. The game has a larger emphasis on storytelling when compared with the original.

Subnautica: Below Zero received "generally favorable" reviews from critics, according to review aggregator website Metacritic.

Andrew Reiner of Game Informer praised the game, saying "Below Zero is what every sequel should be, building upon the established core formula in clever ways to make the new content feel just as exciting and unpredictable." IGN's Leana Hafer commented "New vehicles, new gadgets, and across-the-board tune ups to technical performance and quality of life round out the experience skillfully." Rick Lane from PC Gamer emphasized the game's environment design, calling it "The main area where the sequel improves over Subnautica."