I still don’t love some of the names of these variant constraints. “Little Killer” clues sit outside the grid and affect diagonal swathes of digits, but in this grid, I’ve kept a large area free of any influence, and colored it mint green. Which means that area is free from any clues, too. And yet the puzzle can be solved with just a bit of arithmetic.
Rules:
Normal Sudoku rules apply.
Numbers outside the grid are the sum of all digits along the indicated diagonal. Digits are allowed to repeat if allowed by other rules.
Estimated difficulty: 1.5 out of 5
Solve on SudokuPad