How to play

Press the Play button.
Wait until the shuffling ends.
Move the tiles horizontally or vertically until you find the solution.

Tips & Tricks

You can select a difficulty. Maybe start from the Easy one.
You can use your keyboard to control everything. To see the keyboard shortcuts, press the space bar at any time.

About Portal Puzzle

Portal Puzzle was created as a project for the Flutter Puzzle Hack. The classic 15 slide puzzle is fun until you figure out (or see on internet) how to easily solve it every time. When I had a chance to create the puzzle in the digital form, I thought: why not do something which is not a strict copy of the "analog" box with tiles. Why not allow those tiles to move through "portals"... The rest is history (git log).