Nintendo took the falling-block formula and gave it a theme: Dr. Mario (1990) has you dropping two-tone pills to wipe out colored viruses bouncing in a jar.

It's deceptively deep — clearing viruses in chains, managing the pile, riding the speed ramp — and the head-to-head mode made it a couch-competitive staple. And the music: "Fever" and "Chill" are permanently lodged in the brain of anyone who played.

A puzzle game with Mario's face on it, infinitely replayable, and proof Nintendo could make magic out of the simplest idea.