I did some play testing aswell.
Easy to handle which makes it accessible for everyone.
I don't know if the speed increases after a while to make it more difficult?
I got till level 78 and a score of 9389 but if didn't seem to go faster.
I would prefer that the placed ball got centered to the horizontal middle of the screen.
Now it random locations.
I just spotted that I now get a "You Missed" fault and game over if I missed a target bubble.
Bizarre because I earlier had a few times that I had it go completely around without problems.
Sometimes I failed for valid placements.
Is the outer circle of the target bubble valid or not?
I think in some cases if you hit it on the border at the farmost position of the next one you simple can't make it to the next one.
I wasted 3 or 4 retries and couldn't reach it
Some stars can't be catched either probably due to the above.
The banner is distracting and I clicked it once by accident.
Try considering interstitials once every 5 minutes or so.