=>Extra Modes: On the main menu, hold [L] and then press
cL cR cU cD A cU cD cL cR [START]. Classic and Credits will appear on the
main menu. When you begin a normal game, you will have the option of
enabling Relentless mode.
=>Cheat Menu: Pause the game, hold [L] and press cLx2 cRx2 B A cUx2 cDx2
=>Classic Asteroids: To unlock the classic Asteroids game without using the
cheat code, play until you reach stage 1-15. Shoot the strange green thing.
=>All Ships: On the main menu, hold [R] and press cL cU cR cD B cL cD cR cU