Asteroids

Passwords
Enter CHEATONX as a password to enable the cheat menu. When using cheat mode, press select during game for the cheat menu:

Select returns to game
Up + Down selects Level
Left + Right selects Zone
A button selects invincibility
(001=invincible)

QRTREATR     Unlock Classic Asteroids
PROJECTX     Unlock Excaliber ship

SPACEVAC     Zone 2
STARSBRN     Zone 3
WORMSIGN     Zone 4
INCOMING     Zone 5