Absolutely Essential Games

[Golem]

What are some essential games everyone should play? If you have a repeat, please post it, because I want to see where we agree.

-Super Mario Bros
-Soldier Blade
-The Legend of Zelda: Ocarina of Time
-Tetris Attack

-Space Harrier
-Rocket Knight Adventures
-Wonder Boy III: The Dragon's Trap
-Mega Man 9
-Sonic the Hedgehog
-Super Metroid
-Teenage Mutant Ninja Turtles IV: Turtles in Time
-Streets of Rage 2

[Sky-Fox]

Personally
-Thief
-Deus Ex
-Fallout
-Fallout 2
-Monkey Island 2
-Planescape: Torment
-Final Fantasy Tactics
-Hitman: Blood Money (Don't make me post flow charts)
-Streets of Rage 2
-Sid Meier's Alpha Centauri

But I sort of want to pose another side to the question. I'm assuming you're asking for games I think are essential fun-makers.
But what about games you think are essential for analytical purposes?
-Alpha Protocol (for immense reactivity )
-Arcanum: Of Steamworks and Magic Obscura (quest design)
-Donkey Kong Country 2 (Interplay between music and level design)
-Wizardry (historical long reach)

[Golem]

Hmm, that's an interesting point. I want to ask, how did you arrive at the list of topics for analysis?

I tried to choose essential games based on genre. So Super Mario Bros is essential for platforming, Soldier Blade for shmuppery, Ocarina of Time for action/adventure, and Tetris Attack for puzzle. These games have lots of excellent points that then provide understanding of further games from their respective genres. So while there wasn't an explicit analytical question at hand, I'd say they're still ripe for thinking.

My second list is like a second tier in that sense: almost essential games. Sonic the Hedgehog and Mega Man expand what a platformer can be in different directions from Super Mario Bros, and Turtles IV/SoR2 also make great complements to one another in learning the flow of belt scrollers.

I really wanted to add Wave Race 64 because of how great and awesome it is, but it doesn't give me much transferable knowledge to another racer.

[Sky-Fox]

[Yourself]

Super Mario Bros.
X-COM: UFO Defense
The Legend of Zelda: Ocarina of Time
SoulCalibur II
Crimson Skies: High Road to Revenge
Half-Life 2
BIT.TRIP COMPLETE

Simulation is sorta the purest form of data manipulation gameplay that informs "RPG" systems as well as all kinds of ammo and resource management that extends far into action games, hence X-COM. It feels weird to name such an unknown as Crimson Skies, but to me flight games are an essential realization of 3-space. The two also illustrate the two primary structural alternatives to "levels" - X-COM is a sandbox game and Crimson Skies is objective-based free-roaming. Half-Life 2 is the quintessential cinematic ride, actually translating set-pieces into salient gameplay. BIT.TRIP is there for abstract aesthetics. At first I thought Rez, but Rez is too undercooked.

Most strained omissions:
Ninja Gaiden Black, which more precisely explores combat, but only by repeating lessons about enemy and spatial design you can get from SMB. I think only a fighting game illustrates the breadth and depth of it.
DOOM 2, which again is purer and more thorough shooting than the games included, but tells a story about mazes that I think your life would be better without.
Super Mario 64, which is so pioneering with space but conservative with the action defined on it.
Majora's Mask, because of all the normal stuff said about it with regard to OoT.

[Yourself]

Question to Golem: what makes you limit essential genres to those four?

Question to Fox: why Fallout AND Fallout 2?