Ziriax is a side-scrolling futuristic "shoot-'em-up" set in a futuristic environment, similar to R-Type. The player controls a spaceship-like aircraft that is trying to survive amidst the fire of hostile ships and other enemies. There are five stages in the game altogether; each contains a fight against a boss enemy at the end. Small spheres are dropped by enemies; collecting these spheres bestows the player-controlled ship with various power-ups. These include two additional small ships above and below the main one, an ability to shoot backwards, and missiles that can be shot diagonally.