Army of two game already being sold used

I love it to death, it's like assassin's creed in that I love it for all the glitches and awkward dialogue. For, example, whe you're wounded, your partner is supposed to rescue/heal you, and he'll wind up dragging you for like 100 ft before he does anything, for no reason! And they say F*ck a whole lot. And you can pimp out your weapons, it's basically a squad shooter with rpg elements and added rofl moments.

I just bought the game and haven't cracked the sealed yet since I'm playing Frontlines: Fuel Of War.