The Bug Report -button was showing on the sidebar. It was gray but turned to white when mouse was hovering over. When pressed, nothing happened.
Hmm, I'll review that and see if I can fix it. Thanks for letting me know!
I did some digging and it appears that the problem only appears when playing in the Itch.io App, not while playing in a browser. In the App none of the bottom buttons (tumblr, music, bug report) do anything, but they work fine in browser.
