Empyrion is my long-running (technically, since the 90s) mapping project. The maps have gone through many revisions and occasionally a new map is added, with an explosion of activity last year when I added 4 new maps in one year, unheard of for a slow mapper like me. The oldest have been upgraded from Doom to Boom to Doom-in-Hexen and now to UDMF. The maps are MAP01 - MAP12 and MAP31 - MAP32, with secret exits in maps 10 and 31.
Feedback is always welcome because this project is never finished.
Version without BFGs in coop: empyrion_v39.pk3
Version with BFGs in coop: empyrion_v39_bfg.pk3
Both versions have the BFGs in single-player.
The maps contain Skulltag weapons. Here is an add-on that will change those into standard weapons for game-play mods that don't know what to do with them:
Screenshots are in the second post.
Complete txt file here, and in the WADINFO lump.