Wow this is incredible, thanks a lot for helping me debugging this! I tried a fix, tell me if it works :) It might be a security issue with mac not allowing access to localstorage inside an iframe, you can try it there otherwise if you want: https://dungeon-survivors.netlify.app/.
There is actually no game engine, just a few libraries tied together with a scuffed handmade framework ;) the link is in the description if you're curious about it.
Thanks again for your help, this is seriously awesome of you.