You roll a ball through a maze rendered in proper 3D, seen from just behind and above. Hold I at any point for the controls. The first level is a warm up and takes under a minute.
What makes it work is the view. You can see the walls immediately around you and almost nothing beyond them, so navigating means building a map in your head as you go, and the maze is generated fresh rather than laid out by hand. There is no timer and no way to die, only the slow business of finding the exit and then finding the next one. Nine levels, and the last of them is a real one.