The earliest enormous game with the most amount of disk-swapping yet seen (the game came on six, double-sided disks, and cost $99.95 at its initial release) could only have come from the company that would eventually become Sierra On-Line. Unlike some of their later games, though, the sheer bulk of Time Zone actually worked to the game's advantage. The game's scope was practically epic--thirty nine possible "worlds" to visit, each of which covered a map nearly the size (and in some cases, greater) than most other computer games from this time period. With some creative, atmospheric graphics, and some good puzzles that involved more than one location or time period, Time Zone was actually a pretty good game. Though it could occasionally be repetitive, it could sometimes run slow, and the parser was fairly primitive, even for the period, it still helped to established Sierra as a company to be reckoned with.