In this game, SpongeBob and Patrick control Sandy's submarine and go down Squidward's throat. The player moves the submarine by moving the cursor. Clicking on the mouse button shoots a projectile. Shooting at bubbles scores points. Collecting clarinet reeds gives the following upgrades in order: rapid fire (the mouse button can be held for continuous fire), score x2, score x4, double shot (every shot can penetrate through two bubbles), then the rest gives 500 points. Bumping into a bubble or the edges will remove all upgrades, reverting the submarine back to its original state. Bumping into too many bubbles or the edges will result in a Game Over.
Every time the player shoots a bubble, Squidward will burp.