10,000,000 Points
In the bonus room, collect the letters in order to spell out "JAMES POND". You'll earn 10,000,000 points if you do this correctly.
Cheat Mode
To enable cheat mode, at the title screen hold down Up + Left + C + Start. No confirmation is given. When in-game, press the following for the desired effect.
Hidden Warps
Here are the locations of three of the game's hidden warps.
In the first mission you must save all the lobsters for two warps to open. The first is located in the seaweed to the left of the entrance pipe next to a white rock. Position yourself over the seaweed and push down. This will take you to mission 6.
Also on Mission 1 is a warp that will take you to Mission 11. Once you have saved the last lobster, go to the far left, and jump out of the water onto the ledge. Move to the edge and push down.
You can find a warp in Mission 2 that will take you to Mission 10. Save all the fish from the toxic waste, then move to the right of the entrance pipe at the start of the flat ground and push down.
Level Skip
At the title screen, Press C+Start at the same time. Start Playing and when you want to skip to the next level, simply press A+B+C simultaneously and rotate the D-Pad clockwise.
Open All Doors
Hold Left + C when you turn on the game. When the title screen appears, press Start then release everything. While playing, press A + B + C and rotate the d-pad in a circle to open all the exits.
10,000,000 Points...