Wow! I loved the desktop, it was really fun to play and super creative. I liked the puzzles and I think they have a lot of potential!
I found the puzzles a little easy. I think their difficulty doesn't actually increase with size that much, as the total number of buttons increases much faster than the solution length. So whatever choices you make you can usully solve the puzzle and you don't have to think ahead too much. I think if the solution length was much longer, then there might be fewer possible paths, which would make it more difficult (depending on how you are generating the puzzles)
But anyways, thats just my opinion. This is really good game that fits the theme! I look forward to seeing what you make next :)