Fallout 2, Baldur's Gate 1 & 2, Icewind Dale - what got me into more serious gaming and cRPG genre in general. Still loving them and coming back quite often.
StarCraft II - first "competetive" game I really dive into and man, it's been 8 years and I still play it. I still suck (just slightly less, reached master tier 1 about a month ago) and yet I still keep coming back for more. And that made me follow esport scene, got involved in it, even becoming part of esport organization. Best esport scene ever.
Fear 2 and Bad Company 2 - first online shooters where I was kinda okey-ish and was part of a clan. Times when my internet was as stable as random stalker's aim after a few bottles of vodka, but also times when I had any kind of working internet. Before it I was still on dial-up modem. Yeah.
Stalker - showing that atmosphere can be HUGE part of a game and that "slav spirit" is something real.
Dark Souls - as much as I would like to be into "jRPG" I can't stand their systems. Seriously. Dark Souls showed me that an action RPG made by Japanese company can make sense number-wise. Not to mention the design, art, atmosphere and cruel yet fair combat systems. Loving it.
It is when i started playing CS 1.6 online or on LAN with my friends when i was a kid. Ever since i laid my hands on the mouse that day, I've never stopped playing CS up until now i mainly play CS:GO and some battle royal titles like Apex Legends and PUBG.
GTA San Andreas and GTA Vice City also opened my interest in third person and story-driven games. I realized that there was so much about other games other than fps or competitive titles. It has drawn me more to this massive world of never ending universes of games that i can't probably finish off all until i die.
(Disclaimer: I'm not saying these games were the first to do any of these things, per se, they're just the ones I personally played. Also, these are the years I played them, not when they were released.)
Fair warning, this is going to be long...
1987: Zork - My first all-text adventure, and the one that made me fall in love with game design, text parsers, interactive fiction, programming, etc. (It also set me on a path of computer science until 1993, when I figured out my brain isn't organized enough to see it through.)
1989: King's Quest - The first animated color graphic adventure I ever owned and played. From this point forward (until 1997-ish) I was obsessed with Sierra games, almost to the exclusion of all other companies. I used to buy the 3-1/2" disks off a high school friend who could only use the 5-1/4" disks (the games came with both back then).
1991: Space Quest IV - I heard it on my dad's friend's Tandy PC, and the music and sound effects blew my mind at the time. I knew sound cards were a thing, but I'd never known anyone up to that point whose PC had anything beyond the awful PC speaker. (Though the aforementioned high school friend had an older Tandy for King's Quest I &II, so I had heard some polyphonic music.) At that point it was my mission to get a sound card for my 286 at home. Ever since then I've been all about the sound. (Though I've slacked off in recent years equipment/hardware-wise, letting my mobos do all the work. I need to get a new dedicated card for my keyboard's Cakewalk software at some point. But I digress.)
1993: Sam & Max Hit The Road - This game was several turning points for me. First, it was the first multimedia CD-ROM game to show me that "talkie" versions of games didn't have to be grating on the nerves. Second, it was my introduction to the LucasArts style of adventure gaming, which was vastly different from what I'd been used to via Sierra, where death lurked around every corner. And third and most importantly, it introduced me to Sam & Max, of whom I'm still a fan 27 years later, and whose comics, games, and (to a much lesser degree) cartoon have left a permanent dent on my sense of humor.
1996: Duke Nukem 3D - Despite there having been numerous FPS's before this one, DN3D was the first one I not only finished, but also modded. This and Warcraft II were my introductions to modding/custom content, and it's a path from which I've rarely strayed, even though I've often foregone making my own mods/maps in recent years.
1997: Fallout - Started my love/hate relationship with isometric RPG's, as well as my continued interest in games that offer multiple paths/solutions to a story/plot.
1997: Outlaws - The shooter that quickly replaced Duke Nukem for me, this was the one that motivated me to get my first 3D card.
1998: Magic Carpet - The first game I ever played in actual stereographic 3D (not the bees!!) and made me long for 3D/VR gaming perpetually ever since. (I still wish 3D glasses compatible games had caught on more, as they're easier on the head and wallet than VR.)
1999: Rollercoaster Tycoon - Up to this point, I wasn't really into "God Games" or building/management simulations despite trying several of their demos. Rollercoaster Tycoon changed that, and twenty years later in Planet Coaster I'm still seeing how much I can make little people puke while still getting them to pay to go back on the ride.
[Everquest would go here, but I have a complicated history with MMO's, so I'm not going to try to include any of them here.]
2000: Age of Empires II: The Conquerors - Despite playing Warcraft II back in the day over modem, I had mostly stayed away from multiplayer games (other than MMO's.) I'm not especially competitive by nature, and that also applied to gaming against random strangers online. And most of my friends at the time didn't play online either (and if/when they did, our internet connections were awful back then.) But then I was invited to a LAN party of AoE2, and that all changed. I still wasn't *super* competitive, but I enjoyed teaming up against others and building ridiculously long walls in a vain effort to stop their trebuchets. (Cannon towers helped.) That was soon followed by LAN games of Battlefield 1942 (still my favorite Battlefield game) and online sessions of Warcraft III, as well as the Civ games (which probably should have shown up on this list somewhere) and eventually Age of Empires III. The LAN aspect went away, eventually replaced with broadband, but I still enjoy gaming online with friends, when they're available. (I was not, however, a fan of more or less *having* to multiplay in ME3.)
2002: Neverwinter Nights - Not only was this game my introduction to 3rd edition DnD/D20, it was also the first game system that made it relatively easy for me to make my own campaign. Which... I never actually finished, but it was incredibly fun to work on, and inspired me to eventually write my own pen and paper campaigns a few years down the line. Some of the story bits from my campaign eventually made their way into novellas I wrote during NaNoWriMo. Oh, and NWN was also the first (and so far only) isometric RPG where I played through all available DLC. (The one non-isometric RPG where I've done that is Fallout New Vegas.)
2006: Oblivion - Though Daggerfall was the first Elder Scrolls game I was obsessed with, Oblivion was the first one where I got lost in the world and eventually modded the crap out of it. It set me on a path I've been on to this day of "how much can I mod this game before it breaks?" I even upgraded my video card to get the most out of its visuals. It was also the first game that I ended up playing off and on for half a decade. I probably would have continued to do so had Skyrim not come out in 2011.
2008: World of Goo - Not my favorite game by any stretch, but it's on here for one reason: it's the first game in a long time that I could remember that embraced being DRM-free. It was incredibly easy to pirate it as a result, but out of respect for their decision, I paid full price for it. Since then I've always sought DRM-free versions of games whenever possible, in a perhaps vain hope that it would help increase the popularity and viability of this approach.
2011: Skyrim - Everything that can be said about this game has been said a hundred times over. I'm only including it because this title ramped up my modding obsession to the point where in nine years I've never finished the Civil War, because I'm too busy improving the interface, or sparing Paarthurnax, or adding a hundred new random citizens to cities, or increasing the detail of nearby rocks, or adding entire new lands, or whatever else. And some day, SOME day, I might actually create my own Skyrim mod, an orc-run shop named Morag's Tongs. (Or maybe not.)
2012: The Walking Dead - This game represents two things for me: one, the first time where I knowingly and willingly found myself on the defending side of a game (in this case, the stance that it was even a "game"). In the past I'd been more prone to criticize a title than defend it. And two, it was the first time I can recall genuinely caring about the fate of a character in a game. I was choked up by the ending, and I don't think that had happened to me before. And while the story would have been sad even as non-interactive fiction, the fact that I was "making the choices" (however illusory their impact) added emotional weight and empathy that might not have otherwise been there. I subesequently played most of the TellTale IP's that followed, and enjoying most (if not all) of what they had to offer, while trying to ignore the angry naysayers, all of which has since motivated me to ease up on judging anyone who enjoys a game genre I don't necessarily "get." (Hey there, MOBA fans. How's it goin'.)
2017: Alien Isolation - I played the game before 2017, but 2017 was when I first played it in VR. It's the first game where I've been legitimately scared, despite knowing it's just a game. It (along with a few other titles) showed me that VR has the potential for fairly visceral emotions to otherwise mundane game interactions.
Mine was Borderlands 2.
This was the first game I played with my own PC and friends. My first all-nighters at the University were gaming nights and Borderlands was THE game. Through this game I entered in various groups of society and overcame my social anxiety.
It's still one of my favorite games I play quite frequently. So thanks Borderlands 2!
Dragon Age: Origins. When it comes to RPG I used to mostly play linear JRPGs and this game the first time I played it blew my mind. It showed me that games can have many possibilities and your choices can actually matter.
I've been playing games since the early eighties, starting on the C64, and various consoles. Got a PC in '94.
I've always liked the same types of games, never really been into shooters. I'm into racing games, RPGs(medieval/magic setting preferably), sports games(love the NHL series), adventure games, point and click, and strategy games.
While a lot of games have introduced me to genres, I think the one game that comes to mind that was a turning point for me was Terraria. It made me appreciate survival games, pixel graphics and indie games. One year prior to trying Terraria, I actually told someone that I didn't see the point of pixel graphics that looked like something from the 16 bit era, but I get it now, and I love it.
It prompted me to build my first gaming PC. My store bought Compaq Presario saw me through the original Half Life. But soon after purchase I upgraded the Compaq with a new GeForce 2 Ti GPU and Athlon 600mhz to keep up with new games. The CS HL Mod prompted me to get serious and build my own PC. Abit KA7-100 with the same AMD Slot A 600mhz CPU which I cracked open and used a Gold Fingers device to change the multiplier to 8 for 800mhz.
Ragnarok classic was my very first game.. never thought i would play it until i reached the working age.. i oove mmorpgs with the same feel (TOS). Now im currently exploring battle royale types, moba (used to really hate it bec of how long we have to run per game; but, feelings changed haha), FPS and other fantasy mmorpgs