Audio is now working on Firefox (11.0+ Beta), Chrome, and Internet Explorer. There is background music, as well as effects when you do things like click a button, delete a tower, take damage, or lose the game. The background music is from flashkit.com while the effects are from http://www.superflashbros.net/as3sfxr/?gaming and playing lots with the randomize button.
You can check out the (hopefully) working game on the link to the far right under work in progress.
Besides on the browsers, I’ve got major issues with handheld units. The kindle does not want to play music at all, and crashes at times with the dots freezing and being unable to click or choose anything. The ipad, not unexpectedly, also refuses to play music currently. The next step is to try and figure out what type of browser or computer that the user is connecting with, and disable as many features as needed in order to get the core game mechanics working.
Unless there was a very very important reason to not use a native app, in general I think developers would be better off creating native apps rather than trying to create cross-platform support on mobile handsets using html5. I’ll come back to this in greater detail once my project is completed in another two weeks.