i don't usually talk and then release, but i'd like some input... i would like to make a mod like the old atari game gauntlet: top-down, tons of monsters, different player classes, lots of explosions and gibs!
tweak the chasecam
custom maps, lots of mazes
spawn points for specific monsters
classes: melee or ranged (keep it simple)
player auto levels up after predetermined number of kills
monsters levels keep up with player levels: take the highest level of all players and set new monsters to that level
or skip the levelling idea and just have the player pick up better weapons based on class. or both
use assets from superduper quake
sound good?