Thank you for the feedback. The balls going through the paddle part is a known issue, but it's really hard to address them when they only happen on the web version. I would also like to know what errors are happening with the downloaded version (do you mean the Windows version?).
Update: I released the Windows binaries, so they ought to work now: https://e-net4.itch.io/pkay/devlog/58632/new-windows-binaries