I was fascinated to learn that Jordan was working in the same office as Robert Cook, the guy who was making D/Generation, a game I remember fondly. Like Prince of Persia, it also has an enemy who is a dark version of the player.

(The lineage of the concept is more complicated than one game borrowing from the other, however: The journal entries show that another coworker, Tomi, suggested the dark version of the player, while Robert suggested creating the dark version by jumping through a mirror.)