I've been using Morpheuz for a while now and I really like it. I was even inclined to buy Smartwatch Pro because of Morpheuz!
Whilst I find Morpheuz to be very effective (especially seeing as it's free!) I really think nine hours of recording time can sometimes prove to be insufficient. For example, if I go to bed early, Morpheuz will still wake me at the correct times, but the last portion of my sleep analysis is missing, since I've been asleep for over nine hours. It's not a critical issue but does corrupt my iPhone Health App data somewhat.
I understand that you are working with a very limited amount of resources and hardware that doesn't leave a great deal of room for persistent storage, but I strongly believe that just one extra hour for sleep analysis would be extremely beneficial. Perhaps implementing a mode that allows longer recording but less accurate results, for use on days such as weekends or holiday/vacation?
I realise I may be asking for a great deal from a developer that doesn't even receive funds for a truly fantastic app, but I feel it's a small nick in an otherwise perfect piece of work.
Thanks for the app. Your work has definitely improved my quality of sleep.