Good Game - Some suggestions
- Even knowing the instructions of the game it starts off a bit too hard in the first level for most people. I had issues clearing the first level in the middle due to the high jump.
- On screen UI controls - People are dumb, and I would suggest a semi-transparent umbrella and jet pack icon both on their respective sides
- Slowing down/speeding up - I don't think this mechanic is bad but it's hard at first to get a feel of. Does tapping in the middle do neither and is neutral? I typically always jump with my right thumb causing me to gain more speed always and collide into stuff.
I think you're on the right track, just need a few more UI elements and some easier introduction levels!