Mission Asteroid was just an appetizer. Now for the main course. Time Zone, which uses the same engine as Mission Asteroid, originally shipped on twelve Apple II floppies (or possibly six double-sided floppies; my information is a little iffy here), making it easily the largest microcomputer game ever released at the time. I vaguely remember that Roberta Williams said it would take well over a year for anyone to complete it, and was disappointed when someone managed it within a week of its release. But this story may be apocryphal, or might be true of a different game entirely.
It’s a time-travel game featuring eight areas (seven continents plus one alien planet) in eight time periods, which makes for 64 possible combinations (65 if you include the “Home” setting), although apparently only 39 of them are actually visitable. I haven’t gotten very far in it yet. I’m still in the wandering-around phase, and will remain wandering around for some time. There are a great many filler rooms: mazes of featureless streets, King’s Quest-like grids of empty wilderness. This was released at a time when the size of an adventure game was often measured in rooms, an idea famously discredited by Level 9′s Snowball, with its thousands of useless algoritmically-generated locations. At least Time Zone gives each filler room a unique illustration, which accounts for most of the disk usage.