Note for Firefox users, the "cat video" section is not working, and you will not be able to experience the rest of the app. You are supposed to break the player in a Google Gravity[1] like fashion, but it's broken. They should not "highly" recommend using chrome, but just say it does not work on other browsers.
(In Firefox) I opened the terminal, then deleted an overlay and I COULD "break" the video like you are describing, which lead me to believe it was a "mess with the DOM" kind of pseudo-game, which seems like it was def not the case when I deleted more things and everything broke.
Should they also specify if it works in QQ Browser? What about Safari? Baidu Browser?
I argue that specifying where it doesn't work is pretty stupid. Just specify what you tested it on. It works on those and may or may not work on others. If you'd like it to work on other browsers you can see if you can contact the author to help them with financial support to get the other ones working.
[1] https://mrdoob.com/projects/chromeexperiments/google-gravity...