The game
It was a pretty good game. The grow control I find to be very weird, but I got used to it after a while. Next time maybe you should try to make it right click or middle mouse instead of space-bar click.
The music is simply the best for this type of game. I could not even think of anything better to go with it except maybe, metal? Not really. Another thing is that the game is a challenge. I found myself in some levels to find out really easily, while in others I had to fool around for a bit.
The mass tutorial message I felt came a little too late. Early in the game I could not see why I coudn't grow some of the bricks, which I had to do for me to beat that level, until the mass came into effect. (The affect effect XD I get them mixed up)
The octagon shaped smiley was a cute addition also. At the end I would say it is a pretty hard game at times. I can't wait until a #2. Maybe it'll be new levels designs? Maybe it'll be like Super Stacker. Who knows.