It took me a bit before i figured out what i was doing, but thats life i guess xD
An easy improvement to make is to reduce the difference in detail/style between the bubles and the background.
I'd also recommmend adding some feeback when you influence another bubble(or they you), you can see it through the color change a little bit, but it isnt very clear. (same goes for the pickups).
Its a simple but "unique" game that tries to tell some interesting stuff, but the gameplay does not really match, or atleast, it needs a bit more.
These are relativly small things so nonetheless, its a fun experience, well done