Secret Level:
To get to the secret level, defeat the game in hard mode, then, blow up the glass pyramid in the rooftop stage.

Passwords:
Warehouse - Circle, Triangle, Square, Circle, Circle.
Freeway - X, Square, Square, Circle, Triangle.
Park - X, Triangle, Square, Circle, Square.
Cyburbia - X, Square, Triangle, Triangle, Triangle.
Rooftop - Square, Triangle, X, Circle, X.
Final Battle - Triangle, X, Circle, Square, Triangle.
Secret Level - Square, Triangle, Circle, Square, Square.

Password Codes:
Helicopter View - Circle, Circle, Triangle, X.
Unlimited Ammo - Triangle, Space, Square, Circle, Circle.
Invincibility - Square, Triangle, X, Space, Circle.