Enter numbers 1–4 to play sudoku. Yes, seriously. Normal sudoku rules apply, just with a (not very challenging) 4x4 grid and 2x2 subgrids instead of the usual 9x9 and 3x3.
it now dawns on me that you could just use the clues to set the initial board state and force a unique solution, meaning even a 9x9 would be tractable lol... but i'm happy putting a stop to this here :)