Ghouls 'n' Ghosts

Invincibility:
Quickly type karen broadhurst or karenbroadhurst during game play.
The phrase "Cheat Mode On" will appear to confirm correct code entry.
Note: Falling into holes and having time run out will cost a life.

Alternatively, type delboy at the credits screen.
The phrase "Cheat Mode Activated" will appear to confirm correct code entry.