3 games that changed your life

Street Fighter 2 - first fighting game I ever played
Mortal Kombat - first game I ever played with blood which completely freaked me out
Doom - first PC game and FPS that I ever played that drove my love for game design

In that order

Unreal Tournament - So many memories of this game, some even before I played the game.
Deus Ex - The first PC game I played.
DooM - I'm choosing a career path of level designing and that sort of thing. Doom started it for me.

DOOM
THE LAST OF US
FAR CRY 2/3

DooM
Far Cry 2
STALKER

keep them coming.

Agent USA - The game I remember the most from my Atari childhood. I guess it's edusoft, but the concept is smart and tactical. Weirdly addictive, heh.
Supaplex - One of the first PC games I played and the first game ever I started grinding heavily. Crack cocaine of my childhood.
System Shock 2 - Gave me a very subtle push to pick a tech university over like... physics or diplomacy, heh. Don't tell anyone.

Doom - Because it's Doom
Dance Dance Revolution - Got me through tough times, and got me in shape
World of Warcraft - Gets me through tough times, and got me out of shape

Doom.
Resident Evil.
Command & Conquer: Red Alert.

Baldur's Gate 2 - Made me a nerd
System Shock 2 - Pushed me to become a nerd software reverse engineer.
Doom - The stars aligned and this one-off magic game got made.

Doom
Tomb Raider II
Unreal (the first one)

Doom,
Civilization 5 with all expanded content
Diablo/Baludur's Gate this is a toss-up. they both showed your character from an isometric perspetive. But hack and slash or roleplaying games can be excellent sometimes.

Doom obviously.

Starcraft.

The Legend of Zelda : Oracle of Seasons.

Commander Keen - Marooned on Mars
Doom
DDR

In different ways and at different times in my life, these games were defining experiences.

Doom
Kingpin:Life of Crime
Street Fighter 2

Doom II - One of the very first games I ever played.
Crash Bandicoot 2 - See above.
The Binding of Isaac - Probably my first indie game that I ever played and what inspired me to follow a similar path.

Star Wars: Pod Racer - N64: One of the first video games I ever played.
Team Fortress 2 - PC: The first FPS game and the first M Rated game I played.
Doom - Eventually got myself to start making maps for Doom and join the Doomworld Community. I know, this is an obvious answer.

Bubble Bobble - the first video game that managed to capture my imagination
New Zealand Story - the first video game I set myself to master and learn everything about it

And of course Doom :-)

DooM - Introduced me to a big modding community.
Super Mario Bros. - made me interested in game development in general.
Call of Duty 1 - I love The Soviet campaign.

I love how Doom is in the majority of the lists. Goes to show just how inspirational this game is.

VGames said:

I love how Doom is in the majority of the lists. Goes to show just how inspirational this game is.

Or maybe it's just a reminder of what website you're posting on.

Super Mario Land My first ever game and what got me into gaming.
Goldeneye First FPS I ever played and pretty much enjoyed it, and it had tons of features.
Oblivion My first introduction to the TES series and a very different and enjoyable game which I got a number of mods for eventually.

Doom
Dark Forces II
Zoo Tycoon

Don't know how life changing they were, but here goes -

Zork trilogy (C64) - should need no introduction
Elite (C64) - first sort-of-3D game I got hooked on
Tower of Babel (Amiga) - 3D puzzle game, with programmable robots and a level designer

I'll lump all the PC, pre-Doom3 Doom titles together as one, as they've had an unrivalled impact on my taste in music, preference in games for speed and action, hobby and choice in degree, filling up an unbelievable amount of my life.

The three PS2 SOCOM: US Navy SEALs games are probably the next most major as that's where I first started using Phobus as a handle and first really got into the idea of the internet as somewhere you can share interests with people.

Third place would have to go to either RollerCoaster Tycoon 1+2 (plus expansions) or Forza Motorsport 3+4 for sheer time investment. Playing those through to completion (or not, yet, in the case of the RCTs) has ensured I've not played a load of other games yet.

Doom is the only game that has changed my life.

Other games were just a passing moment, but if I had to list two other games that were influential in shaping my view on video games, they would be Adventure and Amnesia: The Dark Descent.

Doom - my passion since early childhood
Jetpak (DOS game) - my first really fun experience with a custom level editor
Quake 3 Arena - the game I played with classmates, still my very favorite multiplayer game

Super Mario bros .
GTA San andreas .
Half-life .

Doom
Legend of Zelda: ALTTP
and...chess! That counts right? Even though I haven't played in any tournaments, I always enjoyed playing casual games when I was younger.

Flimbo's Quest (C64) - A really cute, very replayable platformer that shipped with the C64 games system console. Great graphics for a C64 game, and a lot cooler than the Amiga version, IMHO.

Lemmings (Amiga) - My most favourite puzzle game ever. The expansion was almost as good, and Lemmings 2 too.

Worms (PC) - Countless hours of hot-seat multiplayer with my school buddies, still playing the series nowadays over the net with my dear brother.

I chose to omit Doom from my list since because obvious ;)

Also omitting the obvious...

1. Chuckie Egg. This is probably the first game that made me think of video games as more than just another distraction. I'm certain another game would have done if it wasn't this one - Barbarian, Rampage and Guantlet all soon followed but Chuckie gets the props for being first. I remember the gameplay felt really smooth and it was so satisfying jumping from platforms to ladders, out manoeuvring the hens and stealing their eggs and corn.

2. Mortal Kombat. This is the first game I remember truly obsessing over. Digitised sprites, blood splatters and gory finishers captured my attention like no other game before. In the arcades it was like the machine was from a different planet to the other cabinets and I overlooked the shallow gameplay because of the mystery of the hidden extras and cool mystical lore. I wanted to know everything about this game and explore it inside out. It inspired a love for fighting games that seemed unshakeable for the next couple of years.

3. Championship Manager 2. Many here will be oblivious to this game and most others will just roll your eyes. You obviously have to be a football (soccer) fan to appreciate a game, which otherwise is let's face it an elaborate spreadsheet. The level of detail and depth of information immersed me into what can only be described as an alternate universe, which I would not entirely leave even when I stopped playing. I'd go to sleep thinking of which position I needed to strengthen, conduct imaginary press conferences whilst laid in the bath, invent chants for my explosive new striker and bore friends with 'amusing' coincedences between my saved game and actual football. I played one version for around 15 seasons and could still tell you my best starting XI even though they are all randomly regenerated players. I purposely don't play this game anymore because of the huge time sink it can become.