Okay, some general feedback:
The tutorial part where I had to look at the sky while "ascending" is not exactly comfortable to watch. I felt nauseous for a moment. It would've been perfect if "I" just stayed on the ground.
Also, there should be a HUD display when some tweets reach the inner circle, like how your screen flashes red on the rim if you take damage in an fps game. It's tiresome to constantly monitor everything at once without something telling you where the tweets are located. Maybe a minimap would be nice, since "I" don't want to run around like a buffoon and end up getting dizzy. For me, I think adding a third person mode as an option would help a lot, since I don't get nausea from other third person games that I play.
And I think this game has a lot of potential. The usual time trials, online death matches, puzzle levels and so on would add a lot more variations to your game. As you may have guessed, I don't exactly like staring at a blank void all day. That also made me feel a bit ill.
I know this is a lot of work that I'm asking for you, but I think it would be cool if you added some of these features that I've mentioned. Wish you the best of luck.