I have the same problem with Opera Stable 26, 12.17 and Developer 28.0.1747.0 both tried in Windows (7) and Linux (Mint 17.1).

It just does'nt work in Opera no matter what OS and what version of Opera you try...

When I click on Embed This Music and click Play it works on all platform and versions.

You can try at this link : http://noisetrade.com/seanwatkins/all-i-do-is-lie