Bowling
The floor becomes a lane. Ten pins. Your marble was already the right shape for this.
You roll into an alley volume and the camera drops to a low chase behind the marble. Rails come up on both sides. There are ten pins at the far end, and they are real rigid bodies, so they will knock into each other in whatever ugly and satisfying way physics decides.
The marble is unchanged. You are still just rolling — same weight, same slip, same overshoot. That’s what makes this the cheapest mode to build, and it’s exactly why it was built first: if the Director can’t hand off and take back control for a mode that changes nothing but the camera, it can’t do it at all.
A strike buys you fifteen seconds. Fifteen seconds is a lot when the whole run is ninety.