- RESEARCH MODE:
AT MAIN MENU, PRESS SQU, UP, DOWN, O, LEFT, R1. NOW ENTER OPTIONS TO FIND RESEARCH OPTION. NOW HIGHLIGHT THE GRID SPACES TO ACTIVATE CHEATS.
1: SMALL ALIENS
2: QUARTER-SIZE ALIENS
3: TINY ALIENS
4: HALF-SIZE ALIENS
5: SEE-THROUGH GREEN ALIENS
6: SEE-THROUGH RED ALIENS
7: INVINCIBLE ALIENS
8: TINY FACE-HUGGERS
9: LARGE EGGS
10: HARD ENEMIES
11: VERY HARD ALIENS
12: FASTER ALIENS
13: RED EGGS & FACE-HUGGERS
14: SLOW ALIENS
15: FASTER, WEAKER ALIENS
16: FASTER, WEAKER FACE-HUGGERS