Subnautica 2, the new underwater survival game from Unknown Worlds, took less than an hour to rocket up Steam's charts. The game has already sold more than 1 million copies, according to a press release, and as of this writing, Steam's charts show that Subnautica 2 is currently the fourth-most played game on the platform with more than 460,000 concurrent players. The only titles with more concurrent players right now are perennial heavy hitters Counter-Strike 2, Dota 2, and PUBG: Battlegrounds.