Normal sudoku rules apply. Nurikabe: Shade some cells (representing water) such that all shaded cells are orthogonally connected, but never fully cover a 2x2 area. Groups of orthogonally connected unshaded cells form islands. Two separate islands cannot touch one another orthogonally, but may touch diagonally. Digits may not repeat on an island. Each island contains exactly one numbered clue, which gives the product of the sum of the digits on the island and the size (number of cells) of the island, e.g. an island filled with 346 is would have a '39' clue (13x3). A '?' may represent any number (not necessarily single-digit). A cell with arrow(s) may be land or water, and the digit gives the total number of island cells in the indicated directions combined, not including itself. Not all arrows are given.