Game manual description
Inside the base, Jim runs through the tubes, avoiding the kitten guards and the large, muscular mutant cats (including the most notable Number Four). The only way to defeat the cats is with the Hamster. There is also hostile floating puffer-fish in the service of Bob.
Outside the base, Jim climbs into one of the submarines and navigates it through very narrow rock passages, attempting to avoid cracking the dome too much, and all the while trying to find a few extra breaths of oxygen at various air-pumps. However, the submarine treks in Down the Tubes are relatively short, with this section taking place mostly inside the base.
The second section which takes you to Bob himself is Tube Race.
In the Special Edition of the game, Down the Tubes has a hidden spot that when touched has a secret alternate Andy Asteroids? level with no asteroids in and no Psy-Crow - just Atomic Accelerators, Asteroid Shields, and Fuel Pods, that takes you straight to Snot a Problem without having to go through Tube Race, the second half of the Down the Tubes. If this route is taken, the player will not have to go through the more difficult section, but will not face off against Bob the Killer Goldfish.
- Tommy Tallarico's theme for Down the Tubes is also used in the second part, Tube Race. The same music is also used for Level 5, the giant laboratory of Professor Monkey-For-A-Head.
- In the 2010 HD remake of the game, the visuals of Down the Tubes and its backgrounds will "ripple," further giving the effect of being underwater.