Just want to share about my app - My Timer.
This app could be used to remind you or others when the set time interval already over via message and music.
Example you want to give/allow someone to play game only for 5 minutes then you could set time interval in this app to be 300 (5 x 60 seconds).
As I can see you do not use any extension...
So what happens if another app is running in the foreground and your app has been closed... do you still get a reminder?
If my app in the background (not killed/terminated) and another app running in the foreground then I can still hear the music when the time is over but for the message I only able to see if get back to my app.