Steven Spielberg originally intended the storyline to be an episode of his TV series
Storie incredibili (1985). It was to be about an archaeological dig on a (presumed) alien planet in the far future. Human archaeologists unearth a large structure and an alien statue, which, in a
Il pianeta delle scimmie (1968)-like twist, turns out to be the Disneyland castle with the Mickey Mouse statue in front of it, revealing the planet was Earth all along. However, the production costs would have been too high, so Spielberg approached LucasArts in 1989 with the idea of making it a video game instead, after being very satisfied with the way
Indiana Jones and the Last Crusade (1989) had turned out. Spielberg and
George Lucas came over to LucasArts and would pitch many other ideas over four brainstorming sessions. The story ultimately went through many changes, retaining only a few elements of the old concept. Spielberg later contributed to the screenplay by suggesting several puzzles and situations, and helping out with character development. He finally sent letters of gratitude to all crew members to thank them for their hard work.
