Betamax is a side-scrolling shoot-'em-up that sees the player at the helm of a fighter ship in hostile space, fighting for survival against wave after wave of attacking aliens. The premise? - take them down, pick up the energy balls they leave behind, and exchange them for ship upgrades.

These upgrades are handled by a power-up system similar to Gradius: collecting an energy ball advances the upgrade meter, and the player may choose to activate the currently highlighted upgrade at any time. Each game begins with three lives, active ship upgrades stay in effect when a life is lost, although they do wear off after a while. On the other hand, some of them have additional levels which improve the power-up's effect if applied more than once.