Make it offline - doesn't work in a browser.
There is a github repo. Just download it from there and click on "index.html" or whatever. Very sorry for the late response from the crustacean. Steve is a rather busy one. Plus, I should note that I'm not the main developer. I just really like this engine.
However, keep an eye out. There will be a critical update that enables custom sound soon. Just be patient and we'll see what happens when it's ready. Thanks from me and the-l0bster. <3
No problem. BTW the latest devlog has some new deetz you probably missed. Steve has been hard at work on this...and...well...that's about it. Good luck on your other project anyway. Be sure to check back whenever possible. I've been buggin' him on Discord on a killable enemies mechanic here and there, but otherwise I've been patient as well.