At first, thank you for this great game! Nice Graphics, a cool game play and a great variety of differently levels.
I would it also recommend to friends, but for this it seems to be too hard. It's not easy to hit the right balls in curves and you have to be very fast. I can't handle the fifth level and I'm sure there many that would play this game but have lower “arcade skills” than me.
Add a possibility to switch the level of difficulty. E.g.: let the ball queue run slower and span more powerups in the easy mode. Especially the end speed of the balls is to fast. With this little change also people which play only from time to time would also have much fun with this nice arcade game!
Of course I saw the “level: easiest level ever (for children)” thread, I hope it was OK to start a new one.
The next version will have level sets. The levels included now (and their difficulty settings) will become the Professional Set. There will also be an easy set with easier levels.