Lemmings

Lemmings launched on the Commodore Amiga on February 14, 1991, developed by the Scottish studio DMA Design and published by Psygnosis. The concept — reportedly born from an animation experiment with tiny eight-pixel characters — was deceptively simple: a horde of dim, green-haired lemmings marches mindlessly forward, and you have to get a set percentage of them to the exit before they walk off cliffs or into hazards.

You saved them by assigning jobs from a set of eight skills — Climber, Floater, Bomber, Blocker, Builder, Basher, Miner, and Digger — turning individual lemmings into living tools that dug tunnels, built staircases, or stood fast to block the herd. When the level timer ran out (or you hit the nuke button), every remaining lemming counted down and exploded in a chorus of 'Oh no!' The chirpy 'Let's go!' squeak became the sound of the whole thing.

It sold 55,000 copies on its first day and was eventually ported to more than 20 platforms, moving an estimated 15 million-plus copies over its lifetime. Critics ranked it among the greatest games ever made, and it's credited as an early influence on the real-time strategy genre. DMA Design would later become Rockstar North — the studio behind Grand Theft Auto — but a generation remembers it first for the little guys who needed saving.