I'm honestly not sure what it could be! I'm also running windows 10 and it worked for Firefox that time too. Seems like you might be an anomaly! Sorry again that it didn't work for you! T_T
Apparently it worked fine in Chrome. Still quite strange that the windows and firefox versions didn't work for me. Well, regardless of all that, this was a fun game! Great graphics and gameplay. I like the way you introduced new mechanics and that you didn't start with everything and had to collect new abilities. Well done!