Parallel Universes
The open world has three dimensions. Every ship has its own level, and that level decides the dimension it flies in.
The stations and regions are the same in all three. The aliens are not: the deeper the dimension, the older and stronger they are. Each dimension also has its own dungeon levels.
The stations and regions are the same in all three. The aliens are not: the deeper the dimension, the older and stronger they are. Each dimension also has its own dungeon levels.