Mega Slide Puzzle

A sliding puzzle, sliding block puzzle, or sliding tile puzzle is a puzzle that challenges a player to slide flat pieces along certain routes to establish a certain end-configuration.
Unlike other tour puzzles, a sliding block puzzle prohibits lifting any piece off the board. This property separates sliding puzzles from rearrangement puzzles. Hence, finding moves and the paths opened up by each move within the two-dimensional confines of the board are important parts of solving sliding block puzzles.