In Qix, players control something similar to a pen nub. Using this cursor, called a "Qix," players must draw lines in the square game board. In each board there are one or more "Stix," odd-looking series of lines that bounce around the board and change direction. The goal of the game is to draw lines that block off sections of the board from the Stix.
Starting from any edge or previously drawn line, players use the Qix to draw lines. When the Qix touches a board edge or another previously drawn line, the drawing is complete, the territory is claimed, and the section is colored in. Players can change course while drawing, to try to claim as much or as little territory as they want think they can get. A certain percentage of the board must be filled each round, within a limited amount of time.
If the Stix touches a player's Qix, or any part of the Qix's line while it's being drawn, a life is lost. If players hesitate too long while drawing lines, a "Sparx" fuse starts at the beginning of the drawing and chases after the Qix until the current line is finished. Two Sparx roam around the edges and lines in the board freely, and if they touch the Qix, players also lose a life.