Hey nice little game. Visually pretty nice and minimalistic, reminded me of a very reduced Osmos. A relaxing background music would make this a cool mediatation game. You could also vary circle sizes and eventually zoom out the camera as you grow bigger to increase this sense of growth.
In my game I also have a similar mechanic, but mixed up with a flight shooter. You collect glowing crystals and make them float a big swarm next to your ship. Maybe you want to give it a try. :)