Y. A. S. I.

Extra modes:
The game has several extra modes to unlock, which can be accomplished by playing a game, the first of which can be unlocked by scoring at least 1000 points. The more points that are scored during a game, the more modes will be unlocked. Note: Erasing the high scores will also erase the Y. A. S. I. screen configuration and the extra modes. The modes are as follows:
Information in this section was contributed by Darryl B..

A: Regular Y. A. S. I. game (no features)

B: Guided missiles

C: Moving bunkers

D: Guided missiles and moving bunkers

E: Cloaking invaders

F: Guided missiles/cloaking invaders

G: Moving bunkers/cloaking invaders

H: Guided missiles/Moving bunkers/Cloaking invaders