Alert X is a single-player action shooter game in which players control a space fighter pilot tasked with defending Earth from an alien invasion. In this game, set in the year 2001, players navigate a side-scrolling environment, battling waves of enemies approaching from all sides, with the ability to move in any direction and unlimited ammunition. It stands out with its classic sci-fi theme, fast-paced gameplay, and the requirement to manage energy levels carefully, as each enemy contact or missile hit consumes energy, risking quick destruction.