I also get this error but only in private browsing mode. It works in normal mode for me.
Viewing post in Yet Another Pacman Clone jam comments
I think possibly it's a part of the code that is trying to use IndexedDB storage. Don't panic! :)
It's a failed debugging experiment. I thought it would be useful to be able save the game's state to persistent storage for debugging purpose. This game is built with Emscripten, it uses IndexedDB for persistent storage. The request to use IndexedDB is still in the code, as I didn't have time to remove that before the deadline. Although the game stores no data there.