Tetris Classic
The Matrix has 66 puzzle games on file for the Commodore 64, released between 1983–1987. 10 of them support multiplayer, including 2 with co-op. They're ranked below by legacy score, so the games that shaped the genre on the C64 come first, with lesser-known picks further down.
Puzzle games challenge pattern recognition, planning and quick thinking, from falling-block games to single-screen logic puzzles.
Typical commitment: quick session (under an hour, or endless arcade fun). Tip: Puzzle games are perfect for short sessions and often have endless or score-attack modes, so they never really end.