well...ok
Why do you still have the buttons on the stage?? Use a pause screen or prompt the user when the level is complete to go to the next level with a window. Moving them randomly around the stage to infrequently clicked areas doesn't solve the problem, it just creates a new problem, of having to find the buttons every single time so you can go to the next level. You could even create tiny little sound buttons and a menu button that take up a third of the space.
The level design is honestly not that bad, sometimes it involves more randomness than I think is ok for a puzzle game, but only occasionally, so that's fine. But why don't you use a shared object to save the players progress?? and also have a level selection screen to go with it?? It's really easy and would improve the game 250%. Even as I bash it there is obviously something inherently fun about the mechanic, but I'm not interested in remembering level codes, or what level I got to, or any of that, so even though I would play it more, I'm not going to...