Sandbox mode can be accessed after earning either the Silver Trophy or the Gold Trophy from Challenge Mode. Entering the "Konami Code" at the main menu screen will bring the player to Sandbox Mode.
|↑ ↑ ↓ ↓ ← → ← → B A|
|"+" and "-"||Change backdrop|
The music and backdrop at the beginning will be from the last tank played in Challenge, Time Trial, or Bonus Adventure. If none have been played, Tank 1's music and backdrop will be used. If the backdrop is changed, the music will not change; it will use the last music from the last level played.
- The only alien that cannot be spawned is Cyrax.
- The only fish that cannot be spawned is the king guppy, although this is likely because king guppies are simply an upgrade from large guppies.
- Star guppies, however, can be spawned due to the lack of available star potions except when the starting tank is tank 2.
- If there are multiple types of aliens at once including Gus, Gus can be hurt with lasers.