A very good 3D Marble Madness game with 2 marbles
In this game you have to roll 2 marbles, a big and a small one to the exit. This game is not time limited, so you don't have to hurry up. There are elevators, moving platforms and door switches.
Only 3 levels, but worth a download ;)
W,A,S,D = Move
Left mouse + move = Camera (you will need that!)
Right mouse + mouse = Zoom
Tab = Change ball
Esc = Exit