Tetris

Tetris is the puzzle that conquered every platform ever made: tetrominoes — four-square shapes in seven varieties — fall into a 10-column well, and your only power is to move and rotate them. Fill a horizontal row completely and it vanishes; fill four rows with a single long piece and you score the legendary Tetris. The stack rises, the speed climbs, and the game ends only when the well overflows.

This build plays with the modern guideline toolkit: a ghost outline previews the landing spot, Hold stashes one piece for later, the next queue shows three pieces ahead, and hard drop slams pieces to the floor for double points per cell. Rotation uses a forgiving kick table — pieces near walls nudge sideways into a legal turn instead of refusing. Start levels 1, 3 or 5 set the initial pace, and gravity tightens every ten lines.

It respects your time and attention in both directions. Hiding the tab pauses the game instantly and the fixed-timestep loop clamps every frame, so no piece ever falls while you are away; the board, hold piece and next queue are written to your browser's local storage after every locked piece, so a closed tab resumes exactly where it stopped. Best score, settings and play count stay on the device — no account, no server.

The engine is pure and deterministic: shapes, rotation states, wall kicks, the 7-bag randomizer (injected RNG), line clearing and the scoring table are plain tested functions. The interface is a thin layer over them — which is why the auto-saved board you return to is always exactly the board you left.