Rise of the Martian Bear is one of the funniest experiences money can buy. For $5 on Xbox (or included on PC) you will get a difficult, but fun, set of missions, as long as one of the main campaigns in the game. Even with a little grinding after beating the main game, the DLC is quite a step up in difficulty, but the new loot does a good job of evening the playing field. You'll still want to play in co-op, since it's much harder than the main game solo. The final boss was quite difficult, but drops some incredible loot, and the extra survival maps are good, too! If you enjoyed Iron Brigade, it's more of that, but with some new enemies and items to keep it fresh.
