If you want, i could put all my other projects on hold and start on that one. Just writing up the creature Raws, possible interactions(Because dammit i like magic!), maybe even some work on one of the Civs - UAC or Imp, probably. Im thinking the civs should actually be a kind of reversal:
Imp: Main playable civ. Build an epic demon fortress, tame wild demons that wander into your little area of Hell. No ability to make advanced alloys, but can throw fireballs - only a 50 tick cooldown.
Spiders: Arachnotrons, highly tech related civ - they have ranged weapons, build funky spider armor, and will come to trade with you. Very weak bodies, but well equipped, due to being cyborgs. Small chance of one being born with a syndrome that turns him into a Mastermind.
UAC: Primary antagonists, they have decent ranged weapons, OK armor, and will come to besiege you demon fortress. They won't have any beasts with them - only hell beasts should turn up in the actual game, you cant have stray puppies wandering around hell unless they zombies or sumfing - so thats a plus. And they have no special powers, either.
Hell Knights: Low populations, but they are numbered amongst the "nobles" of hell. Quite strong - somewhere in between Imps and Barons, kinda like the game. Can throw fireballs with little to no cooldown, are immune to fire(NORMAL fire, that is), and should be quite proud, and maybe aggro as a result - they will come to trade, but a bad deal and they may decide to kill you with a pack of their strongest warriors. Mancubi can be brought with them as seige beasts, even though they are intelligent-ish. Kinda like trolls that can shoot fire. And take hits well.
Pain Elementals can be added, but they will turn corpses into Lost Souls, obviously Archviles can be added, they're basically necros, and pinkies will be kinda common in the wild. I would think former humans are a little meh, i wouldnt bother. Cacos of course, but might make them breathe gouts of dragonfire, so they extra-special. And maybe, just maybe, John Romero's Head can be a new kind of plant. Man, i been on these forums for like two weeks, tops, and i already blown so many minds... (⌐□_□).