Superman cheats and cheat codes for Nintendo 64

Enable cheat mode
Hit C-Up, C-Down, C-Left, C-Right at the main menu. If the code is 
accepted, Clark will say "This looks like a job for Superman."
Then enter the following cheat codes:

Faster speed: Pause the gameplay, and hit R, Z.
Freeze breath: Pause the gameplay, and hit Z, L.
Harder punch: Pause the gameplay, and hit L, Z.
Heat vision: Pause the gameplay, and hit R, L.
Restore health: Pause the gameplay, and hit Z, R.
Skip stages: Pause the gameplay, and hit C-Up, C-Down.