The thing I remember most about Last Resort was actually the first level, which was designed to be a pistol shootout with standard armor and some zombies running around. It was hard to rack up a lot of kills in it, and people tended to get bored trying, but damn if it wasn't a fresh idea. Island was probably the best one though. No wait, Ballroom. Wait, maybe the last one, with all the disconnected themes and rooms? But you'd need a lot of players for it.