I enjoyed this simple little puzzle game, but the lack of rewards (no bells or whistles) nor sounds left something to be desired. Perhaps a small sign holder in the corner that holds up a red X sign when the puzzle is left unsolved, and a green O sign when the level is complete?
Simple, but fun.
Took me a while to figure out how the basic rules worked, but once I did, it was a nice, challenging brain tickler.
I'd suggest little visual improvements, maybe a soothing optional background music and maybe the option to select the tiles you're going to place at the bottom so that you're not double-clicking endlessly once the 7-tile series start rolling in.
Thanks! I think your advices are very good, I will surely use them. Ithought about to make the 2nd release of this game with much more levels so I will improve what I can.