Plays inside your own copy of Beat Saber, on your device, not in a browser tab. Opens github.com in a new tab.
How to play
Have your own copy of Beat Saber installed: the mashup plays inside it.
Download it from its release page on GitHub (it runs on Windows).
Install it as its page says. What it asks for is just below, in the list's words.
Start the game the way its page says: some mashups come with a launcher of their own.
What it asks for
Beat Saber (PC VR) with SiraUtil and BSML, and a user-supplied US Super Mario 64 ROM named baserom.us.z64 in the Beat Saber folder; SteamVR controller mapping may be needed.