Cheats to on the password screen while the game is paused:

NTTSCLNS - Wins the current level
YPTFLWRM - Loses the current level
TSGDDYTD - Invincible Forces
GLTTRNG - More gold and lumber
DCKMT - Build more things at the start of the level
MKTS - Everything built will be done much faster
NSCRN - Shows the entire map