Normal sudoku rules apply. The grid hides a labyrinth: a single continuous region of orthogonally connected cells. All remaining cells are walls. A 2×2 block may never consist entirely of labyrinth cells or entirely of wall cells. Arrows mark ALL dead ends of the labyrinth, each pointing toward the only cell they connect to. Walls form isolated tetrominoes (4 orthogonally connected cells). Wall cells from different tetrominoes can't touch each other, even diagonally. Digits within a tetromino do not repeat and sum to 12. A white dot between two cells indicates that their digits are consecutive. An X between two cells indicates both that the cells are of different types (one labyrinth cell and one wall cell) and that their digits sum to 10. (Not all white dots and Xs are given.)