The object of this game is to slide the largest block out the space at the side of the puzzle. No other pieces are able to slide out of this opening. Pieces can be moved by clicking and dragging. In some situations more than one piece can be moved at once. Alternatively you can click on a piece to move it although this can be ambiguous and a best guess is made.
Although it is possible to create your own initial positions and board pictures this is not yet documented. Please direct and feedback to feedback@grogware.com.
Hope you enjoy playing.
David Grogono