Michael Johnson released Corridor, dubbed "the first 3D game for the iPhone".
Beyond that, Johnson's game also supports the iPhone's accelerometer as the controller for the game.
The instructions are a bit hard to follow without seeing the game, but makes sense when you start playing.
1. If you see protrusions on the left and right, hold the iPhone in portrait mode.
2. If you see protrusions on the top and bottom, hold the iPhone in landscape mode.
3. Do NOT change the orientation of the iPhone while you are in a section with protrusions. This will cause you to crash.