Pieces sit stacked on a board and only the ones with nothing on top can be lifted. Every piece you lift goes into the tray, and when the tray holds three of a colour they clear together. Fill all seven slots without a match and the board is lost, so the real question is never which piece to take but what the board will look like once you have taken it.
A hundred and fifty-three rule sets run from a twelve-piece warm-up to a hundred and forty-four pieces across twenty board shapes — pyramids, towers, wells, fortresses, spirals, hourglasses — with matches of two to six, trays from four slots to twelve, a mahjong rule where a piece also needs a free side, rainbow wilds, face-down pieces, iced pieces that thaw only as you clear, and chained pieces that wait on a partner somewhere else on the board.
Eight power-ups sit under the board: undo, hint, throw back a piece you regret, add a slot, magnet a colour out of the board, reshuffle what is left, reveal the face-down pieces and a bomb that forces a clear.
Two hundred and seventy puzzles span eight tiers. Every one ships with a machine-verified winning line, and the smaller ones carry a proved par — the lowest tray high-water mark any winning line reaches — so a three-star finish means an optimum and not merely a win. The assistant runs a real search and says which kind of answer it has: a proved finish with the number of pieces left, or a judged move when the position is too large to settle.
A board builder sets the shape, the pieces, the colours, the match size, the tray, fourteen deal styles from a barely interleaved deal up to a house special, and every special piece, with a live preview of the exact board you are about to play and its par. Thirty table looks with a colour editor, twelve piece styles, twelve themes, six palettes including a gradient bench of near-identical shades, colour-blind symbols, twelve save slots with autosave, JSON in and out, five languages.