Controls

You play by sliding tiles into the empty space. Click a tile with a mouse on a laptop, or tap it on a phone; any tile sitting directly next to the gap slides over to fill it, opening a new gap where it was.

The whole puzzle comes from this one limitation:

• Sliding a tile only works for tiles right beside the empty square. You cannot lift or jump tiles, so every move shuffles the gap around the board.
• The goal order is the numbers arranged in sequence, left to right and top to bottom, with the empty space ending in the bottom-right corner.

Because moving one tile disturbs its neighbors, solving is about order and method rather than brute force. A Shuffle button scrambles the current board again if you want a fresh attempt at the same size.

The grid grows larger across eight levels, from small, quick boards to bigger ones that reward a solving technique.

Tips

• Solve the top row first, then the left column. Locking in the top row and left column early shrinks the puzzle to a smaller grid, and you never have to disturb the parts you have already finished.
• Work one row or column at a time. Completing the board section by section keeps the problem manageable, since you only ever juggle a few tiles instead of the whole grid at once.
• Learn the last-two-tiles trick for a row. The final two tiles of a row need a small rotation to place without breaking the rest. Learning that one maneuver removes the most common sticking point.
• Plan the path of the empty space. The gap is your only tool, so thinking about where it needs to travel to move a target tile keeps you from shuffling aimlessly.
• Don't disturb finished sections. Once a row or column is correct, route your moves around it. Breaking a solved part to fix another usually costs you more moves than it saves.
• Reduce to the final small square. Every sliding puzzle comes down to a little two-by-two or three-tile finish. Recognizing that end state helps you steer the whole board toward it.

Frequently asked questions