Red circles are red circles, hence the name. They have two white eyes in front of them, pointing in the direction they are going. As they move, they also flash between red circles with white eyes, two white circles with black eyes, to a pair of two red eyes with no body. They appear in the second two forms just as much as the first one, but it is an optical illusion that makes the player see mostly the first form, as red stands out much more. In fact, if the player takes a screenshot of the red circles in-game, they will only get the red version approximately one-third of the time.
Red circles are the most basic enemy in Gunbrick. They are first introduced on level four. They move back and forth either vertically or horizontally. Red circles can be killed with one bullet. They will kill Gun-Brick on contact unless the player is protected by Gun-Brick's shield side.