After upgrading to 0.3, I have the same issue as nicholes. Turning off the vibration fixes this, but not entirely. It just stops playing after a few feconds (10, 20 maybe?) and goes quiet before the sound file starts over. I almost overslept because of this :/

As stated in the changelog, you can't stop the alarm from the UI (menu / kill current task). That's fine to some degree, but not even opening the telephone app via the menu stops it. What would happen if you got a call while the alarm is still playing? It's already so intrusive that I'd imagine you couldn't take the incoming call...

/edit: As as it just turns out, I can't even downgrade because 0.2 has been wiped off the repository... meh.