Codes:
While the intro is playing, press Down, Y, Down, Down, Y. - Practice the bonus rounds

Go to File Select Screen, select Erase Game (should flash), press B, A, R, R, A, L. Now choose a game. - Start with 50 Lives

Highlight ''Erase game'' and press Down, A,R,B,Y, Down, A,Y, then press Select. - Music Test

On game select screen, highlight erase data, press B, A, Down, B, Up, Down, Down, Y and then A. - Bad Buddy Code (Free Switching between 2 players)

Secret Ending:
Do everything in the game to achieve 101% (Win every level, every bonus level, secret bonus level, defeat final boss).

Warp past Stop & Go Station:
As soon as you start the level, walk left back into the entrance. You will warp to the end of the stage, where some manuevering will get you past the level.

Blast through mine cart carnage:
Near the begining jump over the cannon and fall next to the wall underneath. You should get blasted out of a cannon and sent in a cart almost all the way to the end of the level.

Unlimited lives:
To make this work you must use a save game.On your last life die as Diddy Kong.Then press start at the "Game Over" screen. When Cranky Kong appears press down,Y,down,down,Y. You will be brought to a room with 3 of each golden animal.You can enter any of these bonus games as often as you like.To exit, just press start, then select. You will be brought back to the last place you died in your save game.

Infinite Bananas:
In Bouncy Bonanza, after you obtain the frog, you will continuously be brought down this small path. If you jump up, you will get three bananas. Now, enter the cave where you got the frog, and you will fall down again. The same three bananas are there! That means you can do this forever and you will get infinite bananas.