In Qix the goal is to claim a percentage of the playfield by drawing lines. The player is vulnerable in the act of drawing a new line, not just their avatar, but the whole line.
Qix is important because it makes visible the act of play: Nearly each move made leaves a mark on the playfield. A game of Qix creates beautiful form through function. It fits very neatly into the idea of the act of play creating the narrative; but, by laying it all out in front of the player, Qix uses this unlike any other game I can think of.
Unfortunately this aspect of the game is somewhat ruined by the graphical additions of subsequent versions.
Qix was created in 1981 by Randy and Sandy Pfeiffer, and was the first game entirely produced by Taito America. It was, initially, popular in arcades, but enthusiasm dissipated when players learned the game was unbeatable, and there is no singular play-pattern to learn/master.
The Qix hardware was later used by 5 other games:
Apart from the arcade version there are releases for the following platforms: