I guess this one doesn't need much of an explanation. It's yet another version
of the (in)famous "15 puzzle." The pieces are to be arranged in ascending
order, with the hole in the bottom right corner
You get to slide the pieces manually instead of simply clicking on them. This is intended to add a bit of realism to the game. But if you happen to feel that click control is the only decent way to operate the 15 puzzle on a computer, then just press the "Toggle control" button.
The game is capable of solving itself before your very eyes -- in less than 60 seconds. Just press the "Solve" button.