15 Puzzle – Collect numbers

15 Puzzle - Collect Numbers is a browser version of the sliding tile puzzle that has been frustrating people since 1878. Fifteen numbered tiles sit in a four-by-four frame with one square left empty, and the only move available to you is sliding a neighbouring tile into that gap. Get every number back into order, one to fifteen, and the puzzle is solved.

What this version adds to the original is difficulty levels and an auto-build function. The auto-build is not a cheat so much as a sanity check: if you have shuffled yourself into a corner and start to suspect the board cannot be finished, you can ask the game to solve it and confirm that it can. Worth knowing up front, every arrangement this game deals you is solvable. There are no dead boards.

How to Play 15 Puzzle - Collect Numbers

The board starts scrambled. Click or tap any tile that sits directly next to the empty square and it slides into the gap, leaving a new gap where it came from. That is the whole move set. There is no lifting tiles out, no swapping two tiles directly, and no undo button to lean on.

You win when the numbers read one through fifteen in reading order, left to right and top to bottom, with the empty square finishing in the bottom right corner. Higher difficulty levels scramble the board further from solved, which means more moves and more planning, not different rules.

Controls

• Mouse: click a tile adjacent to the empty square to slide it.
• Touch: tap the tile you want to move. Works the same on phones and tablets.
• Difficulty: choose your level from the game menu before you start.
• Auto build: available from the menu if you want the game to demonstrate that the current board is solvable.

Tips and Tricks

• Solve the top row first, then the second row, then finish the bottom two rows together. Trying to place tiles in random order is how most people get stuck.
• Once a row is correct, stop disturbing it. Work only in the rows below it.
• The last two tiles of any row are the awkward part. Place them as a pair by bringing them in from the row underneath rather than trying to slide each one in separately.
• The bottom two rows cannot be solved row by row. Treat them as a single two-by-four block and work in columns instead.
• If you are counting moves, slow down. A few seconds of looking ahead saves a dozen wasted slides.

Who This Game Is For

This is a good fit if you like a puzzle that is entirely about method rather than reflexes. Nothing is timed, nothing chases you, and the board will sit and wait while you think. It suits short breaks because you can leave it mid-solve and pick the thread back up.

It is less of a fit if you want variety. The board is the same every time and the satisfaction comes from getting faster and more methodical, not from new content.

Frequently Asked Questions

Is 15 Puzzle - Collect Numbers free to play?

Yes. It runs free in your browser here on Nelof, with no download, no install and no account needed.

Can every board actually be solved?

Yes. Exactly half of all possible tile arrangements in a 15 puzzle are unsolvable, so the game only ever deals you one from the solvable half. If you are stuck, it is the approach that needs changing, not the board.

Does it work on a phone?

Yes. Tap controls work the same as mouse clicks, and the four-by-four grid is comfortable on a phone screen.

Game Credit and Source

15 Puzzle - Collect Numbers was made by an independent third-party developer and reaches this page through the browser games platform GamePix. Nelof did not create or host this game, and all rights to its code, artwork and audio remain with the original developer. The description, controls, tips and answers on this page were written by the Nelof team. If you are the developer and want this listing corrected or taken down, contact us and we will action it.