Take House of Pain, open up the outside walls, add crossed trenches in the center, and brighten up everything considerably, and you'll get this well-built large arena, equipped for up to 8 players comfortably. Nice roof...

A four-story house, with a yard. Overall, this is quite impressive. The attic is great, and the sniper positions outside are pretty cool. The interior (first and second floors) are a bit cramped... but what would you expect, running around a house with weapons of destruction? Check under the stairs in the basement for a Bungie-esque joke.

Twelve levels. These tend to be huge, open areas, with smaller side areas. Texture choices are odd, in some cases (and overabundant in most). The levels seem to get better as you go higher in the map set (although I encountered a freezing bug in the last level). A couple are extremely high in alien count.

6 maps, mostly variations on Bungie's arena levels (M1 and M2). The biggest influences are Thunderdome, House of Pain, Everyone's Mortal But Me, and Waldo World. Generally nice construction, and plenty of weapons.