So here's the plan. I bought DOOM 3 and Resurrection of Evil for PC this weekend, and I feel that the boardgame could be so much more like the videogame, with more weapons, storyline, invaders, etc. This weekend, I plan to start the second (can't forget about shnar's campaign!) "fan made" expansion, which will include new monsters, weapons, revised stats, etc. If anyone is interested in helping or has some great ideas, I'd be happy to compile them in with mine, or have other people help me develop it. I'm certain that we could come up with our own second expansion, especially if it's a group effort.
My ideas so far:
Monsters (Wraith, zombie tentacle commandos, new marines)
Weapons (double-barreled shotgun, grabber)
Scenarios (with more of a goal than "escape through red door")
Revised stats for existing monsters/weapons (ie melee and ranged stats for monster attacks, some monsters weakened/strengthened)
More ideas are welcome!