I just tried your game, and I kinda like this type of game. The game play it self.
Since you charge for this game, may I ask how old you are? No offence. Just to know a little about the guy behind

(im 22 myself)
I love puzzles, and the idea itself is beloved world over, but I agree with the other comments posted so far about graphics and the lack of sound. The movements could be done a little more smooth perhaps. Anyway, it is stille obvious that you spent a lot of time and effort making this game. My suggestion is, that you forget about selling the game and instead let poeple play it for free in exchange of comments and suggestions, improving your skills. Cus what are money when you can have skills

The good thing about your game is that it does have originality. Pushing a stone and then walk over it. I like that element

I just released a puzzle game myself, an old classic too like yours, but in the mine digger genre. Link:
http://www.java-gaming.org/forums/index.php?topic=14956.msg118537#msg118537 I havent planned on charging for this game ever. Instead I plan on making people able to create their own levels and play each others etc.
But dont compare yourself to Kevglas' tiltilation. Kevglas is very pro and the game is awesome pollished. He seems inhuman

/The Dane