Plenty of work needed.
I know it's not completed but still, here's what I have to say.
1. The start button doesn't work, so fix that. And it should rather be, "Restart".
2. Make it so the thing you are moves around better. It'd be to the point where one little ball got stuck on something and you'd have trouble getting it off. Also it was very slow movement. Make it maybe so there's a powerup or something to make you go faster.
3. Make it so the balls hit the platforms. If they go through them, it makes it pretty hard.
4. Have more then one level. Make different platforms, make you get slower, make the balls come in faster. Just have it so you need to get like 20 balls into the room, then you increase to the next level. Then maybe 30. Just examples.
5. You don't have to, but it'd be a nice idea. To put power-ups in. Doesn't even have to be a lot. Maybe one where you get health, full, half, or even a quarter. Then one where you speed up for a few seconds.. Maybe one where you could fly for a very short amount of time.
6. At the bottom of the screen, or on the sides, somewhere. Make it so you can select through say.. 3 songs or so. Not everyone likes the same kind of music. If you get a type of music the player likes, then it'd increase the chance of them liking it. Music can be a lot.
7. Make a menu. The average stuff, instructions. Not everyone reads the Author Comments. Some people rush to the game. Maybe have credits there. A few other things possibly.
Well, those are a few comments I had. If they help, welcome. If not, oh well. But, good luck in the future.