Four maps. Two are straightforward arenas, but the other two have some unique features... See how long you can stay on the hill on Piston (sniper points are placed particularly well), and InnerSpace is pretty cool.

Imagine Everyone's Mortal But Me with deadly sniper seats... A grenade from the hill into any sniper seat will make life very uncomfortable for anyone in there, whether the grenade hits near them or not. A pretty fun secret that will never be seen by folks not using custom physics models (like the one enclosed).