On the title screen, enter the following:
This code will enable you to do all kinds of codes such as invincibility and all weapons. At the Press Start Screen, press C-Up, Up, C-Left, Right, C-Down, Down, C-Right, R, A, B. If you entered the code correctly, you'll hear a horse neigh. When you start a normal game a Debug menu will show up at the top-left corner of the screen. Press Start on controller 2 to cycle through the Debug menu's. Press the following buttons on controller 2 to activate these cheats at the appropriate menu:
SFX
L or R: FX down/up
Left or Right: FX down/up by 10
B: First person view
A: Third person view
Z: Play SFX
Level Warp
L or R: Level down/up
B: Skip level
Z: Advance to selected level
Midi
L or R: Song down/up
A: Play song
B: Stop song
Global Palette
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
Cheat
Z: All weapons
L: All items
R: All keys
A: Invincibility
AI Debug Values
B or A: GVAR 1 down/up
C-Left or C-Down: GVAR 2 down/up
C-Up or C-Right: GVAR 3 down/up
Fog
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
Left or Right: NR down/up
L or R: FR down/up
Sky Top
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
Sky Bottom
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
Clouds 1
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
L or R: HT down/up
Down or Up: AN down/up
Left or Right: SP down/up
Clouds 2
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
L or R: HT down/up
Down or Up: AN down/up
Left or Right: SP down/up
Player
L or R: DN Down/Up (changes player's character)
GFX
(Values cannot be changed)
AI
A: AI 0/1 (set to 1 to stop enemies)
L: Difficulty 0/1/2
R: Auto aim 0/1
Alpha Palette
B or A: R0 down/up
C-Left or C-Down: G0 down/up
C-Up or C-Right: B0 down/up
L or R: R1 down/up
Left or Right: G1 down/up
Down or Up: B1 down/up