Smarphones have more sensors than any of your consumer electronic devices. Those two games are using gestures and gyroscope as a part of the gameplay, creating an unique game experience that is then used as a differentiator in their marketing.

1. Infinity Blade

Infinity blade is a new Hack and Slash Iphone game, using gestures to control the characters swordplay.  It is amazing to see the quality of the 3D graphics (based on the Unreal 3 engine).

For a review of the games: TouchArcade reviews

2. Star Wars The Force unleashed

Star Wars Force Unleashed is a gesture based action game based around the Star Wars universe. The graphics included are very good and the gameplay is tons of fun.