Subnautica Below Zero's world is smaller then Subnautica's but by far much more detailed. Denser flora, more world-building and intricate level design makes each area just that much better thought out when exploring.

Below Zero contains more "out of water" areas and their added hoverbike makes zooming around on land fun. New creatures to keep the land areas a challenge while the added mechanics such as a cold-weather system keep you on your toes. Additionally, new ways to explore areas, with the newly added module customizable Seatruck, the Spy Pengling, but also classics such as the Prawn Suit make a return.

Unlike Subnautica, Below Zero's main character Robin has more character building then Ryley did. This means that players may have a harder time putting themselves in the shoes of this non-silent protagonist. Below Zero does bring in NPC's (as opposed to the previous sole survivor motive) and builds upon both the Precursors and Alterras lore.

Regarding Early Access:
At its current state, I think it's worth picking up to see how in-depth the world is, how the vehicles handle, and new mechanics play out. Small parts of the story are implemented, but not voice acted. If you're good with a silent experience with subtitles, (that is being reworked throughout the updates) then that is what its current stage is. Like any indie game, it has its bugs that the UWE team is working to fix with each update.

UWE has a very driven team. Their passion for world-building, lore and the end product shine through as each update gets released.

Addendum: At the time of writing this I was a playtester

Subnautica Below Zero's world is smaller then Subnautica's but by far much more detailed. Denser flora, more world-building and intricate level design makes each area just that much better thought out when exploring. Below Zero contains more "out of water" areas and their added hoverbike makes zooming around on land fun. New creatures to keep the land areas a challenge while the added mechanics such as a cold-weather system keep you on your toes. Additionally, new ways to explore areas, with the newly added module customizable Seatruck, the Spy Pengling, but also classics such as the Prawn Suit make a return. Unlike Subnautica, Below Zero's main character Robin has more character building then Ryley did. This means that players may have a harder time putting themselves in the shoes of this non-silent protagonist. Below Zero does bring in NPC's (as opposed to the previous sole survivor motive) and builds upon both the Precursors and Alterras lore. Regarding Early Access: At its current state, I think it's worth picking up to see how in-depth the world is, how the vehicles handle, and new mechanics play out. Small parts of the story are implemented, but not voice acted. If you're good with a silent experience with subtitles, (that is being reworked throughout the updates) then that is what its current stage is. Like any indie game, it has its bugs that the UWE team is working to fix with each update. UWE has a very driven team. Their passion for world-building, lore and the end product shine through as each update gets released. Addendum: At the time of writing this I was a playtester