Pieces sit stacked on a board and only the ones with nothing on top can be lifted; every piece you lift goes to the tray, and three of a colour clear together. Fill the tray without a match and the board is lost, so the question is never which piece to take but what the board looks 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, 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 as you clear and chained pieces that wait on a partner. Eight power-ups sit under the board, including a throw-back for the piece you regret and a reshuffle that rebuilds a winning line as it recolours.
Two hundred and seventy puzzles across eight tiers each ship a machine-verified line, and most carry a proved par — the lowest tray high-water mark any winning line reaches — so three stars means an optimum. The assistant runs a real search and says whether its answer is proved or judged.
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.