Use the mouse to point and shoot. The bolts you fire land and explode shortly after, and will dematerialise any nearby Jeff.
Shooting uses charge which slowly replenishes over time.
Do not let any Jeff reach the edge of the screen, or you will lose health and eventually the game will be over. Once a certain number of Jeff is eliminated, you move onto the next area.
You can trade fire rate for charge speed (and the reverse) by using the mouse wheel or the Z / X keys.
Shoot bonuses for various benefits:
Red cross: Replenish health
Green cross: Replenish charge
Black cross: Bonus points
Yellow diamond: Smart bomb
If a bolt explodes especially close enough to a Jeff you get a small bonus as well.
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