Players face a multitude of Space Monsters in every other round, beginning with the first. The Monsters start at the top of the screen and make their way downwards towards the players' Spacepods; if they reach the bottom without being shot, they begin hopping towards the players' pods.
Spacepods fire in three directions simultaneously: left and right at about a 45 degree angle in each direction and straight up. However, if the fire button is depressed rapidly, the shots alternate by firing in one direction at a time, rather than three directions simultaneously.
With every other screen, players face a wave of rings that start small, split off into other rings when shot, and gradually grow; if one ends up growing to full size then it will suck the player’s Spacespod in, which that ship will be lost.
If the player makes it through all nine different Space Monster waves, all nine different Monsters will appear onscreen afterwards, then one type of Space Monster will appear at random starting with the 10th wave.
This was one of a series of several similar games, with Challenger taking the triple shot mechanism (although the shots were more limited in range) and made the rings into the main enemy of the game, along with adding a warp and super bomb functions for players, a ship for players to dock with for bonus points, and the levels where the rings could suck the players inside occurs on every fourth wave.