Overall this is a very solid entry, so I just want to give two small pieces of criticism.
First: The foreground graphics feel, to me, like they aren't cohesive with the background graphics. I think this is because they are outlined and shaded while the background is flat.
Several of the pixel sizes also differ--that is, the point counter uses bigger pixels than most of the sprites. In my opinion using differing pixel sizes often makes graphics feel less like they fit together. This is of course largely down to personal aesthetic preferences; do whatever you like best.
Second: The music is probably too short--twelve seconds gets old within a couple minutes, in my opinion. That said, it is pretty good music.
I think that the game is overall very good. All of the gameplay seems very solid, and although I have my criticisms of the graphics and the sound, it still looks and sounds great. I like the little personalities that all of the organs are given; they are very cute. I also like the mechanic of generating and transporting resources between the organs.