- Steps counter.
- High scores.
- Ability to pick grid size of the puzzle from 2x2, 3x3 and more.
- Colorful design.
- Game status is saved automagically, you can stop anytime and continue later (or start a new game).
- It works on portrait and landscape orientation.
- It is free of ads and safe, i.e. it requires no special permissions.
Have a look on wikipedia for more details about the game: http://en.wikipedia.org/wiki/Fifteen_puzzle