Under rated!
I feel a bit sorry for this submission because Newgrounds people in general tend to really hate bubble shooters. Maybe there's something wrong with me, but I love them, so here, have a positive review:
The difficulty curve was, for me, perfect - relaxed at first but really quite taxing once you hit the faster levels. The art in the game was really well done, and the slower first levels allowed me to appreciate that.
Additionally, THANK YOU for not using the walls as sticking points. Too many bubblers do that these days, and it makes them nigh impossible to play once they start speeding up. Part of the fun of bubble shooters is trying to break a big chain down the side before it's too late!
As others have mentioned, a 'next ball' indicator might have been nice, but the lack of one made it a bit more exciting as you had to think quickly - maybe an option to turn one on or off might have been the best idea.
Overall, I think it's one of the best bubble shooters I've played in recent times - no bonuses, powerups or gimmicks, just back-to-basics chain-breaking action.