Prehistorik Man (Gameboy)
CheatingDome.com
Hidden developer message
During the introduction enter the following code: Left, Right, B, A, Up, Down, A, B, Right, Left.
Invincible and Level Skip
During the intro, press Down, A, Up, B, Left, Right, B, A, B, A, B, A, Up, Down. Plus, during gameplay, press Select to skip levels.