Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Little incentive for single player repeat play

Fantastic game-play, and the weapons and characters are well-varied. The violence is unrealistic enough to not be too jading. However, the unlockable items are difficult to achieve for single-player, and the only non-works-based incentive is to unlock relatively mundane story lines. Possibly the best multiplayer arena-style game I've played.