HoneyComb
An interesting combination of area styles. Players (mostly) start out in small rooms, but there are teleporters and secret doors to bring everyone together... the main areas are long, open hallways. There are a couple of nice touches (the explodabob pit is always good for killing the guy in front of you, and the textures behind the rechargers are cool). Looks like 4 or so for optimal play...
Levels in map "Honeycomb v1.1":
Honeycomb