The Gunstringer. Namely: there's a secret option on the Kinect shooter that makes it hate you. It's called "Hardcore Mode," and it sounds terrifying. Enemies shoot three times as much, health drops twice as quickly and traps spring from nowhere. Plus, if you die you'll have to head right back to the beginning of the game.
Understand that when we tell you that there's a 50-point achievement for finishing a Hardcore run-through in one sitting called Strings of Steel, it's not so you'll go after it. In fact, it's actually so you'll do the exact opposite and pity those those lost souls who delved into the dark recesses of madness to claim it.