So with the browser version if nothing is visible when pressing Run game, then we need to open fullscreen mode so it can appear. You can enable a fullscreen button on the itch io settings.
When I start the game I had to press Escape two times to see the cursor on the browser, I believe by default the game locks the cursor in the code, so the bug might be coming from there.
I think in one try I pressed Ctrl and it made me see the game camera properly as well, but not too sure.
I hope this helps you find the problem!