Twelve ways to be stuck

This is the deepest shelf on the site, and it is not one kind of thinking. Sudoku and Minesweeper are pure deduction: every move is provable, and guessing means you missed something. Word Rush, Word Grid and Integrame test vocabulary under different pressures, from a timed run to a full Romanian crossword grid. Laser Mirrors and Unscrew are spatial, the kind you solve by rotating the problem in your head. Chess and Dots and Boxes are strategy against an opponent. Memory Match, Slide Puzzle and Maze Sprint are short, clean and surprisingly hard to do quickly.

Deduction beats guessing, every time

The habit that carries across all twelve: before you move, find the square that has only one legal answer. Sudoku always has one. Minesweeper almost always does, and the times it genuinely does not are rarer than players assume. In Laser Mirrors, work backwards from the target rather than forwards from the beam. In Dots and Boxes, count chain lengths before you take a box, because handing over the right chain wins more games than taking the wrong one. A puzzle you solved by luck teaches you nothing for the next board.