UNLOCK MULTIPLAYER CHARACTERS

On the two player select trainer screen, hold Z and press L and R on both controllers at the same time. Giovanni, Ritchie, Lorelei, and Bruno will now appear.

MEWTWO 

On the two player select trainer screen, hold Z and press B, Up, L, B, A, Start, A, Up, and R (Bulbasaur). The game will automatically start. Player 1 is Ash, and Player 2 gets to be Mewtwo! The background will also have an Ash and Mewtwo battle scene.

VERY HARD MODE

Go to the one player screen where you would pick the difficulty level. Hold Z and tap L, L, A, B quickly. Very hard mode should open.

SUPER HARD MODE

Go to the one player screen where you would pick the difficulty level. Hold Z and tap R, L, A, B quickly. Super hard mode should open.

FAST MARATHON MODE

Although the normal speed level in Marathon Mode is 50, you can now raise it to 99. Go to the introduction screen with Ash, Pikachu, Bulbasaur, and Squirtle. Hold Z and press B, A, L, L. If you want the limit to go back down to 50, enter the code again.