Unfortunately the game does not work on Firefox and Mac.
Viewing post in Manifest Violence jam comments
Sorry about that. Seems to be a common problem with Godot games.
If you're up for it, you can try Safari, or better yet, grab the downloadable version. The itch.io app makes it pretty easy to manage games, just like Steam. Even on Safari, it'll crash after a while, so the download is the best choice.