The missing file is music, and it plays fine on the game page on itch.io.
I did not provide a separate zip file for download thinking that people would just play online. It appears the itch.io app is downloading just the .html game file without the supporting folder of media, which doesn't make a whole lot of sense.
I have just uploaded a complete zip named BPoL-Download.zip. Try downloading and playing that (or running in the itch.app if that works?) and see if you still get the errors.
it doesn't launch from the launch button at all now. i took a look at the files downloaded and it downloads the webversion now so all one has to do is go to the files and open the index.html (default main file for website for those that don't know). i didn't look at the files it downloded before so i can't really help out with why it worked before and not now. it wasn't a matter of not including the files (as in all files) as the images (jpegs) were visible when 'doing research' about the tape, though it looks like their was audio file issues (maybe not inlcuded or in a different location, their could even be a translation issue between software which uses incorrect file paths due to name compressions).
I just updated the updated itch desktop app on my Windows 10 machine, and both Breeding Princesses and another game in the same system installed and loaded and ran fine with the music from the ZIP files it downloaded from the main page.
Have you updated the desktop app? If it still gives you problem, delete the game file and re-download (choose the ZIP version if you have a choice) and install it. If that still doesn't work, perhaps you might need to rip and reinstall the itch desktop client?
Itch support confirmed there were problems with web games in the previous app. Update to 25.0.0 (https://itch.io/app ) and all seems well!
Let me know if you have any other issues, and thank you for alerting me. I actually really like the app now!
