good concept the grapghics are pretty good but the physic could use some work and in one of the tutorial levels it said there are two balls you only need one to go in its a paradox it would have been nice if the menu was first and had an option to look at the tutorial levels and the main levels also more levels would be nice hope this criscism helps :)
I got a(n) A- on medium! My score was 209340 with a max combo of 50. I scored 29 perfects, 21 greats, and 0 goods. I got only 0 bads and 10 misses! I was playing on 5 speed and had 0 crazy options on. Great game, I like it! Play it here: http://www.thorgaming.com/games/3926/feel-the-beat.html
its obvious that you haven't made too many games before so thisis a very good job i think that you should work on grapics and maybe add some music and a reset button increase speed and this would be a very good game. 5/5