Cheat

Code

All weapons

Up - Up - Down - Down - Left - Right - Left - Right - B - A

Full ammo

B - A - X - Y - Left - Right - Left

Full health

B - A - B - A - Up - Up - Down - X

Invincibility (health never drops below 1)

Down - Up - Down - Down - Up - Right - Left - Right - Y - X - X - A