This an awesome alarm clock!! I am a very deep sleeper... Before the app I usually woke up late for works every day, but with this app (in the shake mode), I wake up almost in the same time!
The only think is that if your iPhone is in SILENT mode (vibrate) the alarm clock WILL NOT work!!! Actually it will, however if the iPhone is in SILENT mode, your alarm will set also in SILENT (vibrating). So if you forget to put your iPhone to ring, forget it, your alarm will not wake you up, unless you wake up easily (then I would not recommend the app).
It would be solved if an additional functionality (like the original alarm clock from iOS) that would set the alarm independently of the cellphone mode (Silent, Vibrating or Ringing)!
Thats it!