There's a rare bug in the launch version where if you kill a game just as you start one it can put the whole game in an unstartable state. We've fixed it, but unfortunately haven't been able to update the itch version yet because signing requires getting to an office computer and we're not in the office right now.

So if you run into this issue, until we can update here, I'd recommend trying the Steam version. Sorry for the inconvenience!