I've also updated the compatibility detection code to use the JavaScript player for IE 10 and 11, since the Flash version cannot do HTTP Range requests (and thus cannot seek). These still use Flash for audio output, but all the decoding is done in JS.
There's a funky bug where the player state gets confused if you play through a second time after completion, still have to track that down.
Also still need to rework the MobileFrontend integration to be more stable; Jon's suggested refactoring it to just the internals so I can piggyback directly on the existing mobile media viewer overlay (perhaps with an extensible hook?) without trying to extend the still-fragile overlay API. Will also need to add seek controls on mobile. :)