From Real Sudoku3D:
Real Sudoku3D breaks through the barriers of conventional 2D and 3D Sudoku games, and creates a truly realistic 3D Sudoku experience. Regular Sudoku is played on a 9 by 9 grid. Real Sudoku3D uses 9 layers of 9 by 9 grids.
All the layers follow standard Sudoku rules, whether viewed as Faces (from front to back), Levels (from top to bottom), or Slices (from left to right).
The Real Sudoku3D interface lets you dive right in and see the game from any perspective. Toggle layers on and off at will. Turn and move the game around, zoom in and out, or fly straight through! When gliding through the cubes you feel like you can touch and play with the three dimensional numbers within the cubes, providing a true multi-dimensional gaming experience.
Flexibility is one of the greatest features of this 3D Sudoku game. You can select a cube to enter your choice of number, or make notes on which numbers remain possible. Hide or display the notes during any point in the game. Need some help? There is also a built in error-checking function which can be turned on and off with the click of a button. If you need additional support, visit the Help page on our site for step-by-step instructions as well as Sudoku solving strategies and helpful tips.
Optionally use Auto Notes for effortlessly seeing possible choices, and strategically customize your notes from there.