The object of the game is simple - race your ship to the end of the tunnel collecting as many powerups as you can before your time runs out.
There are 20 levels to play. Each level starts red and progresses to orange, yellow, green, blue and finally purple before the level ends. Use the color to know how far through the level you have progressed.
In order to get to the end of the level in time, you must accelerate your ship by changing your physiological measurements.
The basic Game Settings window lets you choose a level, the control method (joystick, autopilot) and lets you choose a basic feedback mode (Ship Speed, Fog, Tunnel Transparency, etc.).
The more complex Custom Settings window allows you full control over the configuration of Inner Tube and allows you to play without the tunnel, without powerups, on autopilot, without time limits, and with any combination of game feedback.