Features:

- Four difficulty levels (easy, normal, hard, very hard).
- Tutorial with several techniques (from beginner to advanced) for solving the game.
- Unlimited undo and redo.
- Game saving.
- Notes.
- Auto noting empty squares.
- Auto updating notes.
- Square coloring with two colors for advanced techniques.
- Errors checking (manual and automatic).
- Screen rotation control. Check screen rotation for playing in portrait and landscape or uncheck it for playing in the mode you prefer no matter the orientation of the screen.