Diamond L(2,1) D(24,5,4,0,0,0)
Moderate difficulty
Like a standard Sudoku except that the boxes are pushed over sideways so that the problem wraps side to side but not top to bottom.

Film L(2,3) D(27,9,9,1,1,0)
Difficult
Similar to the regular 9 by 9 Sudoku but the squares have lumps in the top and bottom. The problem wraps top to bottom but not side to side so the overall geometry is a cylinder.

Jigsaw L(2,1) D(23,7,7,0,0,0)
Moderately difficult
As regular 9 by 9 but the normal 3X3 boxes are irregular shapes

Samurai L(2,1) D(121,5,4,0,0,0)
Not particularly difficult, just lots of work to solve.
Effectively 5 intersecting 9 by 9 Sudoku problems.

Sudoku 9X9X L(1,1) D(22,5,5,0,0,0)
Moderately easy
As regular 9 by 9 but must also have unique characters in each diagonal, highlighted.

3D 3X3 Cube L(2,1) D(9,2,2,0,0,0)
Easy
True 3 dimensional problem, albeit a very simple one. Each 3X3 square is one plane of a 3X3X3 cube. Consider the squares stacked on top of each other. There are 9 planes in this problem each of which is a 3X3 square which must have no repeating characters. A couple of the planes are highlighted in colour.

Diamond L(2,1) D(21,7,6,0,0,0)
Relatively easy
Here the shapes are pushed over to become diamonds. This wraps side to side but not top to bottom.

Film L(2,1) D(25,4,3,0,0,0)
Moderately difficult
Similar to the regular 9 by 9 Sudoku but the squares have lumps in the top and bottom. The problem wraps top to bottom but not side to side so the overall geometry is a cylinder.

Jigsaw L(2,1) D(22,13,12,0,0,0)
Moderately difficult
As regular 9 by 9 but the normal 3X3 boxes are irregular shapes

Toroid V L(2,1) D(20,7,7,0,0,0)
Difficult
The normal 3X3 boxes are replaced by vertical stripes (helices) which wrap around the problem. These stripes join the left side to the right side and the top to the bottom so that the overall geometry is a doughnut (torus).

4X4 Cube L(3,1) D(39,5,4,0,0,0)
Moderately difficult
Strictly a 2 dimensional problem since only considering the outside faces which are laid out onto a plain. There are 16 Characters which cannot repeat in any band or face. 3 of the bands are highlighted. There are 12 bands and 6 faces, each with 16 Cells. There are 16 possible characters so I use a standard hexadecimal character set: 0,1,2,…,9,a,…,f.

Diamond L(2,1) D(20,11,10,0,0,0)
Moderate
Here the shapes are pushed over to become diamonds. This wraps side to side but not top to bottom.

Film L(2,1) D(23,7,7,0,0,0)
Moderate
Similar to the regular 9 by 9 Sudoku but the squares have lumps in the top and bottom. The problem wraps top to bottom but not side to side so the overall geometry is a cylinder.

Jigsaw L(2,3) D(26,11,10,2,1,0)
Difficult
As regular 9 by 9 but the normal 3X3 boxes are irregular shapes

People L(2,3) D(17,9,9,1,1,0)
Difficult
The shapes have “lumps” on each side to become quite irregular. They look to me like little people. This problem wraps top to bottom and side to side so the overall geometry is like a doughnut (torus).

Film L(2,1) D(23,4,4,0,0,0)
Moderate
Similar to the regular 9 by 9 Sudoku but the squares have lumps in the top and bottom. The problem wraps top to bottom but not side to side so the overall geometry is a cylinder.

Jigsaw L(2,1) D(21,11,10,0,0,0)
Moderate
As regular 9 by 9 but the normal 3X3 boxes are irregular shapes

Samurai L(2,1) D(114,7,6,0,0,0)
Not difficult but time consuming due to the size of the solution
Effectively 5 intersecting 9 by 9 Sudoku problems.

Sudoku 9X9X L(1,1) D(22,11,10,0,0,0)
Moderate
As regular 9 by 9 but must also have unique characters in each diagonal, highlighted.

Toroid H L(2,1) D(22,6,5,0,0,0)
Difficult
The normal 3X3 boxes are replaced by horizontal stripes (helices) which wrap around the problem. These stripes join the left side to the right side and the top to the bottom so that the overall geometry is a doughnut (torus).