
The series’ A.I. Director, which in the first game handled how many zombies pounced on you depending on how well you’re doing, got an upgrade. It not only controlled the flow of zombies, but would try to force players to take more difficult paths in a level, and reward players with extra health packs and ammo if they were doing well. Though the original development team went on to create the asymmetrical multiplayer shooter Evolve, nothing has quite matched the visceral thrills and scares of Left 4 Dead 2, which stands as one of the pinnacles of modern co-op gaming.
Thief II gave the player all the right tools for the perfect heist, along with interactive maps for writing notes. It rewarded taking your time, and of course, listening to some of the best guard banter in any game to date. Silently sprinting along rooftops, ducking through secret mansion passages – the game didn't just make you feel like a thief, it made you feel like a master of the craft.
Quick, name your favorite modern first-person shooter. Maybe it's Call of Duty, or Halo, or Counter-Strike. All of those games—and dozens, if not hundreds more—owe an immense debt to Doom. Developer id Software's 1993 classic pit an unnamed space Marine against the forces of Hell, plunging gamers into a high-intensity battle for Earth. Another id title, Wolfenstein 3D, may have arrived a year earlier. But Doom became a true phenomenon, introducing millions of gamers to what have become bedrock principles of the genre, from frenzied multiplayer deathmatches to player-led mods that can alter or completely overhaul a game's look and feel.
Mario's brick-breaking, Goomba-stomping antics were enough to mesmerize the world's gamers in Nintendo's idiosyncratic side-scrolling Super Mario Bros. games. But 1996's Super Mario 64 transported Nintendo fans into Mario's universe as no other game in the series had, simultaneously laying out a grammar for how to interact with 3D worlds (and in its case, divinely zany ones). At more than 11 million copies sold, it was one of the bestselling games for the Nintendo 64, but its real impact was arguably off-platform, where it tectonically shifted the design imperatives of an entire industry. As Rockstar co-founder and Grand Theft Auto V cowriter Dan Houser put it: "Anyone who makes 3-D games who says they’ve not borrowed something from Mario or Zelda [on Nintendo 64] is lying."
X-COM’s magic is how it makes the war to defend Earth from a vastly superior alien invasion force feel so intensely personal, even with its extremely dated (but expressive) graphics and spreadsheet-like interface. Part of this comes from the way that every decision you make, from where on the globe you place your bases, to which alien technology to research, to whether to spend your soldier’s last few time units to reload his weapon, crouch, or take a Hail Mary shot at a distant alien, has enormously high stakes. Choose right, and your team of alien hunters will gain a leg up on the battlefield from advanced weapons (like the guided Blaster Launcher missiles), armor, or tactical positioning; choose poorly and literally everyone could be slaughtered – or worse, transformed into drooling zombies to serve as incubators for horrific Chryssalids.

In nearly three decades no game has supplanted Super Mario World as the best game ever made... Which is stupid. I’ll get to that in a bit. Super Mario World is a relatively simple game to describe. It’s a Super Mario game, and we all know what that means: Mushrooms; perfect running and jumping action; and a giant world to explore, crammed with secrets.
The first title designed by Nintendo mastermind Shigeru Miyamoto, 1981's Donkey Kong not only brought Mario into being, it also popularized the platformer—games in which a character has to climb or jump onto platforms. After dominating the golden age of arcades, Donkey Kong went on to have a massive influence on future Nintendo titles, ranging from the NES's Ice Climber to the Wii U's New Super Mario Bros. U. Even today, demanding expert timing and patience, it remains a timeless joy to play. (What's more, Donkey Kong was arguably the first game to feature hazardous barrels.)
Cutscenes were one of the driving forces behind the success of PC gaming in the late '90s and Blizzard was regarded as the king when it came to jaw-dropping visuals. They took things to an entirely new level with StarCraft and the Brood War expansion in 1998, though. Not only were players treated to an excellent RTS experience, but their reward for completing sections of the campaign were evocative visuals that further immersed you in a world where humans are losing a war against brutal space aliens.
Sam Fisher's third adventure is actually three masterpiece games in one. In the campaign, a stunning real-time lighting engine and open mission design allows you to play in countless different ways: total stealth, full gunplay, or a gadget-fest (shoot a Sticky Shocker into a puddle as an enemy walks through it, anyone?). Memorable locations like the lighthouse, bank, Hokkaido (with its "anti-ninja flooring"), and more made every mission memorable. Game 2 is the four-mission two-player co-op campaign, in which two young agents work together in a side story that runs parallel to Fisher's adventure. You literally have to play together, from boosting each other up to high ledges to going back-to-back to scale elevator shafts, the co-op mode committed to cooperation in a way no other action game had. And then you had Spies vs. Mercs, which took the asymmetrical multiplayer mode introduced in Pandora Tomorrow and refined it into something truly unique in the gaming world. Agile, non-lethal spies playing in third-person view faced off against slow-moving but heavily armed mercs that saw the game through a first-person helmet. It was tense, riveting, and brilliant.
