Ozone Force was my entry in the first Bullet Physics game contest. It won second prize which were a couple of useful text books.
The game was created entirely in Blender. Coding was done in Python to make the key controls user-friendly.
You can download the exe for Windows & blend file, or see the original entry page.

The keyboard controls in Ozone Force were very unique. I call them "sticky" controls. The camera follows your ball like any other 3D game camera would, but the only useful control in most marble-like games is forward for this control scheme. sticky controls make every direction have the same affect as forward. You can hold down right or left and the ball will continue to go in that direction even after the camera has turned to follow behind it up until you let go or press another direction (usually forward).

The goal of the game is to make it to these goal points in the least amount of time possible.