Mine Cells — FAQ
Notes
The dimensions carry thick fog and their own skies, which is deliberate: seeing a long way would give away a room layout that is meant to be walked into. A night vision effect will let you read a dark Prison corridor if you would rather see it.
Because the dimensions generate from a room grid, the rooms are placed on a coarse spacing rather than in every chunk. Landing in a stretch of empty terrain does not mean generation failed - the next room is simply some way off.
The portals are the only way in and out. Nothing here changes the overworld, so an existing world can add the mod without its terrain being touched.