The other day I stumbled upon a Sliding Puzzle Game on Wikipedia and I thought it would be a fun weekend project to build it in JavaScript.
It runs on node so you can either clone the repo and run it locally or you can use the Repl.it iframe to run it in your browser (just press the green button):
The keyboard controls might be a bit odd at first, and I got into a closure hell with mixing functional with global variables, but it works and that's as much effort I'm going to put on this.
You can find the source code on GitHub https://github.com/jpedroribeiro/SlidingPuzzleJS