A small arena with a surrounding corridor, and a subterranean waterfilled network of access tunnels. Nice attention to detail, but there are two problems. The tunnels are pretty long, with no exits other than at the ends, which makes it easy to get trapped (I'm not really fond of underwater netmaps, anyway), and the weapons/ammo are really light. More than 2, and you're gonna be duking it out with bare fists.
A small map in the Everyone's Mortal But Me style. Nice flow, with fast-moving elevators to get you on the hill, well-judged heights, and good cover potential. Weapons are limited to fusion pistols and the occasional spnkr... groups of more than 3 might find ammo to be a problem. Oh, yeah, and if you leave aliens on, you might have some trouble keeping an eye on your friends... Update changes the aliens present from jugs to hummers (still need to watch 'em, though...) and ups the ammo quite a bit. (Adds assault rifles, as well.)
Two tiny arenas, joined by a corridor. Pretty mapmaking... extremely high carnage rates with any more than 2.