 In 1984, Nakamura created a relatively exclusive contracting company, christened Chunsoft in honor of "Door Door" diminutive hero.An expanded version of the game, branded "Door Door mkII", was released three years after the original in February 1985.The game was ported to MSX computers, NEC's PC-6001, PC-6001mkII, PC-6601, PC-8801, PC-8801mkII, and PC-8801mkIISR models, Sharp's MZ-2000, and Fujitsu's FM-7.