Door Door

Players control Chun, a small, egg-shaped creature outfitted with a baseball cap. Chun is relentlessly pursued by a quartet of aliens traveling in deterministic algorithm paths. The most predictable aliens Namegon and Amechan follow Chun in the most direct path possible, Invekun deviates and follows roundabout paths using ladders, and Otapyon shadows Chun's jumps.

The player's objective is to trap the aliens behind sliding doors positioned throughout each level, courses composed of platforms conjoined by assorted ladders. To trap the aliens, players approach the door from the side its handle is on, open it by running across it, lure the advancing villains inside, and shut the door before they escape. Trapped doors cannot be opened again. Chun can jump to avoid the aliens, who can kill him on touch.

Inspired by the popularity of personal computers in the United States, Yasuhiro Fukushima decided to set up Enix, going into the PC game business market, in 1982. Fukushima wasn't a programmer himself, and Enix, in a broad sense, was simply intended to be a publishing company. To pool the talent of individual game designers, Enix sponsored a national programming contest. Three hundred programs were entered into the contest, and the first prize went to programming prodigy and high school student Koichi Nakamura for his puzzle game, Door Door.

Yuji Horii placed in the finals of the same contest with a computer tennis game; both were subsequently hired by Enix and the rights to Door Door became property of Enix. Enix published the game on a wide range of Japanese computers, including NEC's PC-8801, Fujitsu's FM-7, and Sharp's MZ-2000. With sales exceeding 200,000 copies, Door Door was a huge success. The popularity of the budding console market prompted a 1985 release on Nintendo's Famicom.