At various points in gaming history, a title has come out that's not simply well-done and enjoyable, but important as well. These are the games that broke technological ground, or launched entire genres, or even just reached the height of popularity and turned new people into gamers.
This is the game that started it all, of course—not only the arcade revolution, but also the dominance of Atari over the '70s and early '80s game market. No, it's not much to look at today, but anyone who knows anything about game history has to acknowledge the impact it had.
Space Invaders proved that a simple concept, if well-executed, could captivate gamers for decades. Of course, I could just as easily have picked lots of other arcade classics from this era: Pac-Man, Galaga, etc. Even those of us who were born after these games came out have spent hours racking up high scores on them.
Back in the early '80s, some Nintendo employees in America were stuck with a bunch of arcade machines for a failed shooter game called Radar Scope. To salvage the machines, they tried refitting them to play a different game, and that game was Donkey Kong. This was a first in a lot of ways: the first highly successful platforming game, the first appearance of Mario, the debut of Donkey Kong himself, and the appearance of Nintendo as a force to be reckoned with. It's a little primitive to play today, having been designed to eat quarters at a frustrating pace, but it's still easy to see why it was a watershed moment in video game history.
This game hold up amazingly well today—especially if you play the version on Super Mario All-Stars, with updated graphics and the ability to save after each world. An '80s childhood is incomplete without countless hours spent searching for warp zones, hidden blocks, and the demise of Bowser.
I'm not really a fan of sports games, but my younger brother and I played countless matches against each other on this classic. (We had it for Super Nintendo, but it was also available on numerous other platforms.) Of course, the original was much in need of improvement—you can have a great deal of success running fake punts every play—but it was fun nonetheless, and it launched a whole era of sports gaming.
Of course, this is just one of several classic PC strategy games, but the genre deserves representation on this list. It was awfully hard to start a new Civilization—or a SimCity, or much later a family of Sims—without sticking around to see how everything turned out.
It's difficult to pick just one classic id Software FPS. Wolfenstein 3D got the ball rolling, and the Quake games were great advances in technology, but it was Doom that showed the world how much fun first-person carnage could be. Also, it introduced the chainsaw, and the world of gaming was never the same.