Very addicting concept. The chain reaction bubbles are satisfying to pop, and I ended up sticking with this game for a while to try to beat it (which I did)!
I do think some of the mechanics are too unclear. In particular, for anybody stuck on that yellow bar on Level 4: I had no idea you needed to click ON the yellow bar first, then pop yellow bubbles. I think the instructions could have been more clear there.
Oh, and I liked all the music except for the one that plays during the first squid fight (I think). There's this dissonant high-pitched squeal that hits this particularly evil-sounding frequency, and no matter what volume it's at, I just couldn't stand it while wearing headphones. Thankfully, you only used that track once.
But like I said, I love the chain reaction thing! Overall, great job!!