This was nice to play! It's actually very similar to a game idea I had a while ago, so it was cool to see it. 
For feedback, it feels way too easy, maybe add stronger enemies that spawn with bubbles. Also, I would definitely add diagonal movement.

This was cool to play. I like the idea here and after I got used to the controls they started to make sense. Lots of potential, like others have said. 

A really cool concept and with some more polish would be really fun.  Some small things that could add a lot are better sprites/background, camera scaling with size, and difficulty increasing overtime.  Really cool game that has huge potential!

Fun game idea! You should try to add some wiggle to the bubbles for some nice game feel maybe even a popping animation and a rainbow-like background similar to what bubbles make.