A bunch of people have sent me links to an article about a programmer who proposed to his girlfriend through a video game, and have noted the similarity to my own proposal using PyStage.
It's not quite the same thing. The system I wrote was an animation system I wrote from scratch, and not a game. This other programmer hacked a pre-existing game. Both are interesting feats in their own ways. (Interestingly enough, the original plan was for me to propose with a full game, but then I realized that the cutscene was complex enough.)
Still, there are certainly similarities in the nerdiness of the proposals, but they're not really surprising. Good programmers take pride in the nerdiness and cleverness of programming, and what better way to propose than to make full use of your craft?