Number puzzle - number klotski 4+

Refined look and feel, new levels added - now you can play 3x4, 4x5 too

A simple yet amazing number riddle puzzle - Number Klotski, is a variant from the traditional Klotski puzzle.
It is slightly addictive, please take rest when you feel it is needed.
The puzzle can be saved and restored, no worry about losing progress.

The rules to note:
1. There is only one empty cell.
2. Every other cells are assigned with a unique number.
3. Each time, only one block or few continuous blocks (horizontally or vertically) could be moved towards the empty cell.
4. The mission: to bring the cells to their numerical order, left to right, then top to bottom.

The challenge ranges from 3 x 3 to 9 x 9, and includes a few non square levels such as 3 x 4 and 4 x 5.

The mission is not only about finding the correct sequence of moves, but also doing it with the least moves if possible.
It requires strategic planning, problem-solving, and the patience.

* History of Klotski Puzzle
The Klotski puzzle is a captivating sliding block puzzle with a rich history that has been enjoyed for centuries as a form of entertainment and mental stimulation.

The Klotski puzzle is believed to have originated in the early 20th century, although some sources suggest that it may be even older.