A closer look
Hitting an invisible wall breaks immersion, but being eaten alive by a sea monster perfectly preserves the illusion of freedom. In open-world survival games, developers must eventually restrict the map size. Instead of using immersion-breaking barriers, Subnautica surrounds its playable area with the Ecological Dead Zone. If you swim too far into this pitch-black void, the game spawns massive, aggressive predators that multiply the further out you go. If you survive, you realize there's nothing out there anyway, and organically retreat.
