Queens is a logic puzzle played on a grid split into coloured regions. Your goal is to place exactly one crown in every row, every column and every colour region — and no two crowns may touch, even diagonally. It is pure deduction, with no general knowledge or maths needed, so anyone can play.
Yes. Every daily Queens puzzle is generated and verified to have exactly one valid solution.
It is just a note to mark cells you have ruled out. It helps you think and does not affect the solution.
By how quickly you solve the puzzle — faster solves score higher.