This is a rather amusing concept you have here. The blue green pallet is smoother and feels more fittng to the theme. Lovely piece.

I really like the animation!

You should do a follow up of them fitting together in pixel heaven.

I meant to make him cry because he's lonely, because I'd like to think that when they're removed they move to some kind of pixel heaven, with lots of adjacent pixels of its own kind. But I have to admit I haven't given it enough thought...

Is it crying just because it's lonely, or cause it knows it's going to be obliterated as soon as it's found? 

I chuckled from the thought of it. This is a pretty nice piece.