This would be a fun thing to dink around with: a level editor for the Apple II version of Prince of Persia, one of the most innovative platforming games of all time.
If you have any interest in game design and development, be sure to also read Jordan Mechner’s journals / diaries from his time making Karateka and Prince of Persia — a time capsule into the mind of a successful ~18-year-old game dev auteur.