Like its predecessor, the 2018 game Subnautica, Below Zero is a deep-sea survival sandbox experience on the Planet 4546B. The new game takes place a full year after the original game's events, building on its story.
“Subnautica: Below Zero has grown and evolved based on community feedback in Early Access and we’re excited to finally launch the full-blown sequel to Subnautica,” says Ted Gill, President of Unknown Worlds. “After two years of implementing player feedback and adding new features and content, we’re excited to welcome players back to the depths of Planet 4546B to find an all new experience on PC and console.”
The early access build has been received pretty well by players over the last couple years, currently holding a 'Very Positive' rating on Steam. Phillipa gave Below Zero a go back when it first launched in early access, and said that while it was "a little rough around the edges," it was still a very enjoyable Subnautica experience.