I've found a small bug called "Ghost of the Pawn",
which can be quite confusing:
if you'll make the move En Passant
En passant - Wikipedia, the free encyclopedia
and take the enemy's pawn, it will not disappear;
but it will lose the ability to move and eat your chessmans,
and other chessmans can go through it,
only the image of pawn will remain, like the ghost,
until another chessman will move to it's square to replace the ghost.
Why? Because of the algorithm:
the image of enemy's (and your) chessman which was taken
didn't disappeared, but was replaced with image of chessman who took.
But in the En Passant move one pawn will not replace the image of another,
because after the move it will stay on another square.
How it could be fixed?
Just make the image of the taken chessman
to disappear Not to be replaced.
And, also, have you any luck with MoveSound?
P.S. Hope you still support the Chess game.
Because, with those two small but important changes,
it'll become just perfect!