Alien Storm is a side-scrolling beat 'em up game that combines action with strategic gameplay. Players can choose from three distinct characters, each equipped with unique attacks and special abilities, to combat an alien invasion across multiple missions. The game features a variety of environments, from urban streets to alien motherships, where players must defeat waves of enemies while completing objectives such as rescuing civilians or destroying UFOs. The gameplay is enhanced by the ability to collect energy and power-ups, which are essential for unleashing powerful special attacks.

With a total of six missions in the arcade version and eight in the Mega Drive version, the game presents increasing challenges as players progress. Each character's special attack utilizes energy, requiring players to balance their offensive strategies with resource management. The game also includes unique boss encounters and shifts in gameplay perspective, such as shooting gallery sections, adding variety to the action. Overall, Alien Storm delivers a fast-paced and engaging gaming experience for fans of the action genre.