Psychophobia is a Doom II mod which can be played with gzdoom and skulltag. Features: new weapons, new monsters, new textures, new music, new sounds, new decorates, new Hud, new maps, and many other different things.
Absolutely the biggest mod I've ever played. Its great, a very WIDE variety of demons to blow up into bloody bits, and new maps with a great atmosphere. I give this a 9/10! The only thing that bugs me is that I can't really find the storyline, but other wise, this is a fantastic and well done Doom modification!