The only reason I bought this game was the level creator. However, it can be very frustrating at times:
1. The back button, which returns you to the level you were playing, has no confirmation button. I would at times accidentally press it, and all my effort and handwork would be for naught. Please enable the "are you sure?" window.
2. You cannot test-play your own levels before posting them [to Twitter]. You run the risk of creating a level with multiple easy solutions, which you don't want having. That's why I NEED the ability to test play my own levels. Or better yet the ability to see the different solutions to my own level (that'll be difficult but let that be a challenge to the developers of this app).
3. As mentioned, you HAVE to post your levels to Twitter, to all your family and friends to see. I get that this is a publicity stunt, so that this app has a larger player base, but it can be very annoying to others as well as to myself.