Rise of the Martian Bear." In exchange for 400 MS Points, or five Earth bucks, the DLC grants you four new maps (two of which can be played in Survival mode), a new boss fight, a diverse armory of beefed-up weapons, more customization options and, most importantly, a sombrero.
Those disappointed by Iron Brigade's lack of ambidextrous salutations will be pleased to hear about the free title update launching alongside the patch. It'll jolt your character's left arm to life, allowing it to perform gestures just like the one on the right. Oh, sure, the patch also ensures compatibility between regular and DLC-equipped players, but you have to appreciate the little things -- even when the game's about big stuff stomping around.