Hmm interesting.
Really love the concept. Because it's about getting as many collisions as you can to gain money which I have never seen before in an idle game. It is also really simple. I like the special skill because I didn't expect that so It caught my attention to figure out what it means.
I think this game is really good in the end game and med game, but the beginning is just too slow for most people and they quit before they see the interesting stuff.
Some ideas that might make it better:
1. Add something you can do with your mouse to gain extra collisions, maybe if you click on the ball it gets an extra instant push. Often good idle games besides being idle have something the player can do, e.g. in cookie clicker you can click on the cookie. I think this will really have an impact on your score because I feel like most people quit this game early because they can't do anything with the red ball to some sort of own control on this game.
2. Add newgrounds highscores. This way people are motivated to continue playing to beat eachothers scores.
3. Balls can also collide with eachother, could make the gameplay more interesting when you have more balls.
Some other things I liked about later in the game. I liked how different balls have different special effects. maybe describe the special effect of each ball in the upgrades?
Definitely wouldn't quit this game you really got something here. Just needs some work on the rough edges. Some finetuning, playtesting, finetuning ...