It probably won't work when you're running the game from your own file system. So although it may look broken if you run it from your hard disk, if you upload it to the site, it should work properly.
You might be able to get it to work on your own PC if you change this bit...
src="//embeds.audioboom.com
to
src="https://embeds.audioboom.com
But potentially it may still not work, as Chrome puts restrictions on what HTML files are allowed to do when running locally on your machine. The solution is to upload it and check that it works there - when you upload, you can make it unlisted if you don't want it to be public yet, so you can test it yourself.