In Torus Trooper you fly a ship through a twisting and turning tunnel, or half-pipe, so it's not really a torus you're flying through. A timer is continually counting down, and you play until the time runs out. Some events can add or remove time, for instance getting your ship destroyed loses you 15 seconds, while getting certain number of points, or defeating a boss will give youa time bonus.

The game has three difficulty settings: Normal, Hard, and Extreme (no 'easy' here!)

• Wikipedia entry
• Torus Trooper website