Level select:

Press A, R, Z, Up(2), C-Up, C-Down(2) when "Press Start" appears on
the opening screen. The phrase "Missions Open" will appear to confirm
correct code entry. Any level and battle mode may now be accessed. 

Invincibility:

Press A, Z(2), Up, Left, Left-C(2), Down-C when "Press Start" appears
on the opening screen. 

Turbo crazy mode:

Press B(2), R, Up, Left, Down, C-Up, C-Left when "Press Start" appears
on the opening screen. The phrase "Got it" will be spoken and a
message will appear to confirm correct code entry. 

Psychedelic mode:

Press A, R, Left, Right, Down, C-Up, C-Left, C-Down when "Press Start"
appears on the opening screen. 

Wire-frame mode:

Press L(2), R, Z, Left, Right, C-Up, C-Right when "Press Start" appears
on the opening screen. 

Gore mode:

Press Z, Down, C-Up, C-Left(4), C-Down when "Press Start" appears on the
opening screen. The phrase "Gore mode" and a sound will confirm correct
code entry. 

Paused opponents:

Pause game play and press R, Z, Right(2), C-Up, C-Left, C-Right, C-Down. 

Unlimited main weapon:

Pause game play and press A, R, Z, Right, C-Up, C-Right, C-Down(2). 

Unlimited secondary weapon:

Pause game play and press B(2), Z, Left(2), C-Up, C-Left, C-Right. 

Unlimited Solaris missiles:

Pause game play and press B, L(2), Z, Up, Down, C-Up(2). 

Unlimited Titan missiles:

Pause game play and press A, B, L, Up, Up, C-Up(2), C-Left. 

Unlimited weapon energy:

Pause game play and press L, Z, Left, Right, Down(2), C-Down(2). 

Invisibility:

Pause game play and press A, Z(2), Up, Left, C-Left(2), C-Down. 

Instant kills:

Pause game play and press B(3), L, R, Left, Down(2). 

Unlimited Stealth Mantle:

Pause game play and press Up(4), Right, Down, C-Left(2). 

Quick start:

Press the reset button when the first screen appears. When the game
restarts, press Start to skip the series of opening screens. 

Bonus characters:

There are eight bonus characters in the game: Septre, Ex-Cop, Jo, Nubia,
Cerbero, Mephistofun, HK-5, and Dr Nepenthe (Nutta). Find and kill them
during normal game play or on one of the eight battle mode levels. The
corresponding character may now be accessed on the Biker selection screen.