UNBELIEVABLY addictive.
I played the first level and thought to myself, "What the hell am I doing. This game is dull and simplistic; a cool name its only real merit." But for some reason, I kept going, and kept going, and kept going... I've been at it for nearly three hours now, plowing through early missions again and again to unlock the challenges, wielding the ridiculously awesome leveled-up weaponry and enjoying the occasional comedic dialog between the main characters. Despite all the flak and premium content, this is an extremely solid game.