This is a pretty fun game. It's basically Gears of War's Horde Mode, or CoD: World at War's Nazi Zombies, with some tower defense elements. I've been having a good time in single player, but as the description should indicate, it seems built for co-op. There's also a competitive mode, which is basically the regular mode plus some control over how your robots attack the opponent's base, but I haven't tried it yet. It's 1200 points ($15 in actual human currency), which seems to be the standard price for an XBLA game these days, but I think there's definitely enough content here to justify it. If anyone here gets this, add me as a friend so we can play together; I'm insanolord on Xbox Live as well.