Subnautica is a sandbox or open-world game that is very similar to classics like Minecraft or The Forest. The twist is that the adventure takes place beneath the ocean of an alien planet.
You can download the game from Steam in Early Access format, a sort of developmental demo. Despite its being treated as a "demo", so to speak, you can't download it for free.
Beneath the Sea
Subnautica begins with a catastrophe: your spaceship crashes on an alien planet covered by a huge ocean. You have no choice but to use your ship's emergency capsule as a base while you explore the waters in search of a possible escape plan.
Subnautica is a combination of Minecraft and The Forest. On the one hand, you dive beneath the ocean looking for material to create buoys, oxygen tanks, and even a submarine. On the other hand, you have to search for food and arm yourself to face off against the most aggressive fish in the ocean.
Subnautica's object-creation system is more complex than usual. It will take you some time to get used to it. In that sense, we missed something in the tutorial.
The graphics are impressive, making that one of Subnautica's strong suits. You'll feel like you're exploring a strange ocean full of alien fish. The environments are full and varied, spurring you to dive deeper each time... despite the dangers it brings with it.
Explore the Mysteries of the Ocean
Subnautica has a way of keeping you enthralled. You'll want to build your first submarine. You'll want to explore caves in search of minerals. You'll want to discover what kind of fish lurk in the next area. You'll want to equip yourself as much as possible to explore the rest of your sunken ship. You'll want to build bases scattered throughout the ocean...
If you get excited about the mysteries of the sea, make no mistake: Subnautica is what you were wishing for.