Astroids

On the Title Screen when PRESS START is flashing Hold Select and press the following buttons in order. You will hear a sfx prompt, when the cheat is activated.

Unlock Classic Asteroids Game = Circle Circle Circle Triangle Square Square Circle
Unlock Fourth Ship = Triangle Circle Circle Triangle Square Circle Square
Level Select = Square Triangle Circle Triangle Triangle Square Circle
Once in the game, you can change levels and zones and turn collision off by:
1. During game play, press Select and Start simultaneously
2. Select level, zone, and collision state using the directional pad
3. Press L1

Classic Asteroids Game Codes
+1 LIFE = up, down, left, right, circle, square, X, triangle
99 LIVES = up, X, down, triangle, left, square, right, circle
INVINCIBILITY = down, down, up, up, circle, square, triangle, triangle