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.