When the Start game screen appears press X, X, B, A, Y and Start.
Infinite Detonators
When the Start game screen appears press B, X, B, X, B, X, B, B, B, Y.
Extra Continues
When the Start game screen appears press A, B, A, Y, A, X.
Debug Menu
When the Start game screen appears press and hold
L and R on controller 2, then press AABB XXYY ABXY ABXY
on controller 1. When you want to access the Debug Menu
during the game, press L and R on controller 2.
Invincibility
Enter the Debug Menu code. While playing the game, on controller 2, press and release Select, A, B, X and Y simutainiously.