Normal sudoku rules apply. Shade some cells in the grid such that all shaded cells form a single orthogonally-connected region and no 2x2 square is fully shaded. Each unshaded region must contain exactly one clue cell. Each unshaded region is an “X-killer cage”. Digits within a cage may not repeat and must sum to the total given in the corner of the clue cell. Additionally, the digit placed in the clue cell must equal the number of cells in the cage. The cell with a grey circle must contain an odd digit.