What is the game that changed your life? why?

All the older Sierra On-Line adventure titles (Larry, King's Quest, Space Quest, ...) because it forced me to better my english since you had to type in whatever you wanted your character to do. Started playing those with an english/french dictionary in hand and now my english is much stronger thanks to this.

Let's see, as with some of the people above, there are many games that changed my life. But, here are the most notable ones:

Pokemon Red and Final Fantasy Tactics: For expanding my imagination and introducing me to RPGs.

Super Mario Bros 3: One of the first games I got on my GBA, and was my introduction to Mario.

Sonic Adventure and Sonic Adventure 2: For giving me a sense of adventure (as the name suggests), and introducing me to Sonic.

Grand Theft Auto III and Simpsons Hit and Run: For giving me a more mature sense of humor.

Halo and Half-Life: These were my first FPS games.

And finally, Legend of Zelda - Oracle of Seasons: Same reasons as Pokemon, Final Fantasy and Sonic, but this game also made me realize that you could program games to react differently on certain platforms, like only accessing the Advance shop by playing Seasons on a GBA.

Chrono Trigger was a key influence on my life. So many actions taken had many consequences. When you opened a chest, when you defeated Black Omen, the whole shebang with the Fair in the Prologue... Even facing Lavos itself changed. While you could fight and change things and act to help people, sometimes your actions led to worse situations or in spite you didn't change a thing. Sometimes you could prevent a tragedy, sometimes you couldn't. I learned two important things: even the smallest things can have the biggest impact, and I really hate time travel.

Similarly, the Final Fantasy series has a big influence on my life. Most notably: 1, 4, and 7.
Final Fantasy 1 was my first JRPG. God, I must had been 2 when it came out in the US? I've played video games literally as long as I could remember. FF1 introduced me to tactics and more importantly gave me options. Final Fantasy 4, I was a bit older when I played it. A more complex story with good people doing bad things and bad people being redeemed. Final Fantasy 7, naturally, I all but jumped on. For the longest time I thought Sephiroth was a woman and I was distraught when Aeris was killed. To clarify: I was 8 when the game came out. Long-standing party-members dying and staying dead was unfamiliar, hated, and horrifying. Also, the discovery that not even my own lead character's memories could be trusted was another shock.

Dunno. Planescape: Torment had a huge impact on my inner world with being such a thoughtful game, but I don't remember any game that changed my life completely. Sometimes I think I can even write a videogames history brochure to explain the whole impact of games on my life, but I'm afraid only some to none readers would be inerested in examining it. :) So I dunno, sorry. Some of game OSTs have heaten up my interests in music, some have altered my way of thinking in some subtle way (Blizzard games, Deus Ex, many other titles), but I can't name one that was the hugest life-changer in my whole lifetime.

Tabletop Dungeons & Dragons, the best video game never created.

P.S. For the faithful, I've been getting into 3.5 Eberron lately-- BAAWWWSSSS.

Russian Roulette.

Shadowgate. Because of this game I was able to read at an early age.

And Planescape: Torment changed the way I look at a few things.

Who remembers that skiing game that came with windows back in the 90's? 'Twas the first game I ever played, and the game that led me into the amazing world of games

None really. I did not grew up with gaming being a regular thing I did. Also, I always had older computers, so it was outdated for the current games.

I suppose Lands of Lore: The Throne of Chaos did make a bit of a difference; probably the first time I played a full color game and it introduced me to classic rpg. And I suppose playing MUD's at some point, developed my interest in MMORPG's and multiplayers (though I left MMORPG's a long time ago, too grindy, communities were meh, etc.).

Counter Strike 1.6, started my addiciton and i spent 10years playing that game...

Counter Strike 1.6 /later Source, because these games are my childhood. had fun with them, met a few cool people and many idiots. i'm more than happy that i've stopped playing them, just too big time waste and my (social) life is much better since i stopped.

This will show my age, the game that changed my life was Karateka, the old one.
When I was very young, I when to this one place that allowed you to pay to play a game for half hour.
So yeah, this was the first game I played on a PC, after giving it a try, i decided i wanted to study PCs, and well, here I am today! :D

Mirror's Edge. It changed my perception on how you press the lift button.

There have been a LOT of games that have changed my life. I'll list my first big life changer, and my most significant life changer below.

Phantasy Star (Sega Master System): My first RPG ever. I was very very young, and had no concept of what an "RPG" was. Starting a game in a town talking to people... For a long time... Then exiting and getting into 1-2 fights before dying, and realizing that I had to grind? Mind Blown. Games could be strategy and story. That moment, I knew games would be part of my life until my dying days.

Lunar 2 Eternal Blue (Sega CD): I was at a young age, and this game solidified a lot of political/religious/personal beliefs for me. The subtlety of story and gameplay being mixed together (Stats reflecting story, and character interactions), was a big deal to me at the time. The idea that government should govern and not parent. In religion, humanity are like children, and the idea of God being the parent, that at some point we have to grow up and find our own way and once we do, we can never go back. Also made 2 lifelong friends (I consider family) because of this game (over 20 years so far). We each identify with a particular character from this game, and our relationships to each other strangely matched in the same way too. Strangely, we all met months before the game came out, but it wasn't until it released and as we played it, that we realized we were all playing it, and that we had those same things in common.

Jazzjackrabbit 2 my favourite game from childhood!

MGS 3, because it was the first (real) shooter i ever played.

rapelay, the title say it all

Sonic The Hedgehog.
Despite his bad fandom, I found some great people who drive me to find my own passion for my future career. Also met some IRL friends who helped me in some occasions.

Sex, most definitely. One of its main outputs are children, which by any definition are a major lifechanger.

Touhou Project – it's game play, the music, and the fan works like: music, manga, etc...

once i was a professional player of cs 1.6 played that game till 7 years straight. finally left it. made so many good friends from it. lot of memories! :)

Team Fortress 2 - the one and only game I dislike actually rewarding me for not playing it. With games worth my time. That's awesome, isn't it?

Eurotruck Simulator, I'm a truck, now.

Real Kanojo

Football Manager, the original series back in the 80s by Addictive Games. It's what got me into games because it was the game my father played, it made me learn BASIC so that I could add in new players and stats on my own (early modding), and has me hooked all these years still when other and better football management sims came out.

Without that, I might have just limited myself to action games and platformers, if I had stayed with games at all.