Sliding Tile Puzzle

Click on Goal button to see what the solved puzzle should look like. After clicking on button 2 for a new game, click button 1 to check for solvability.

Goal: rearrange the tiles 1-15 going from top to bottom, left to right,
by clicking the highlighted tiles. Click on button 2 to start a new game.

1. Is this puzzle solvable?

2. If not, start a new game.