Tetris
Seven shapes, one well, one rule: rotate and slot the falling pieces into complete lines before the stack reaches the top.
The 1984 puzzle game everything else in the genre gets measured against. Tetrominoes fall one at a time into a ten-wide well; you rotate and slide them, complete horizontal lines to clear them, and the pieces drop faster every few levels until you can't place them in time. There is no winning screen, only a top-out.
Most browser versions follow the modern conventions: a next-piece preview, a hold slot, a hard drop, and much bigger scores for clearing several lines at once. The four-line clear that gives the game its name needs a deliberately maintained one-wide gap, which is the trade every player learns to make between safety and points.
Controls
Arrow keys to move and rotate, Down to soft drop, Space to hard drop.
Tips
- Keep the stack flat except for one deliberate well; a bumpy surface leaves holes you can't clear.
- Use the next-piece preview to place the current one, and decide where S and Z go before they arrive.
- Never bury a row under a hole. Digging it back out costs far more than the points you saved.