Hmm, I'm not sure what's preventing it from playing. Renpy (the game engine) should work on windows 8.1, and I can't find similar problem on the internet.
Sorry, I wish I could help more.
Oh, yeah I think that's it. Between 0.2 and 0.3 version of Pan Hero, I updated Renpy to the 8.0 version which has discontinued 32 bit support according to this https://renpy.org/doc/html/changelog.html#platform-support-changes