This was really beautifully made! Not just the art but the gameplay, music and integration of the theme felt very natural and polished. Well done! I was following your updates on discord, so I was a bit curious to see how the game turns out, and its really good! I know you have 2 more game modes planned, but i think this itself has quite a lot of game time in it.. can be treated as a puzzle game and also a relaxing chill experience. The satisfaction when 2 pieces combine to form a new one and free up more space is really awesome, and just highlights how well youve managed to integrate the theme!
The only minor issue i faced (and maybe this is just me, i havent read the other feedback) was in recognizing the different spheres. There were some i could very clearly distinguish between, but some were too close together for me. Again this did not take much away from the fun factor, since 'messing up' is not punished too much. But maybe you could look into that.
But overall superbly done, congrats!