You can't talk about gaming in the '90s without talking about Cyan's 1993 smash hit, Myst. That's no hyperbole either, as Myst was the best-selling PC game for almost a decade, until people started finding creative ways to murder their virtual families in The Sims, which finally outsold Myst two years after its 2000 launch. That's a fairly impressive feat for a game that ran on a 386 with 4MB of RAM. I remember fawning over the graphics at the time, although I'll admit that I didn't have the persistence at 11 years old to actually beat the game on my own. Thankfully, my favorite BBS (Sort of a predecessor of the Internet, for those of you born after '85 or so.) hosted an in-depth text-only guide which helped me through the trouble spots.
Being a slower-paced game than shooters like Doom, Myst focused heavily on immersive graphics, which you actually took time to appreciate and marvel at as you pounded your head against the desk trying to make the requisite leap of logic to solve one of the more esoteric puzzles. Myst's surprise success launched a franchise that persevered until 2005 with Myst V: End of Ages.
Unlike previous titles on the list, 1998 strategy hit StarCraft was far from being the first RTS on the market. In fact, StarCraft developer Blizzard had already put out two games in the WarCraft series, which made Blizzard's presence on the RTS scene known. All the same, StarCraft has largely become the poster child of the genre, and established a huge international following, as well as being considered one of the best video games ever.
What made StarCraft special was the fact that it offered three distinct, yet fairly balanced races to choose from, rather than offering only two sides, which often mirrored each other. This, alongside the multiplayer, is what really made StarCraft stand out to players and critics alike. Requiring a blisteringly fast 90MHz Pentium processor and a staggering 16MB of RAM, StarCraft is hands down the most demanding of the games on the list, which is no surprise, really, given that you could amass armies of dozens to hundreds of Zerglings on screen simultaneously.
If you've ever wondered what the origins of the colloquial verb "zerg" are, look no further. The Zerg race was known for producing many cheap, underpowered units, which, when attacking en masse, could simply overrun an unprepared enemy. Playing StarCraft online taught you very quickly that you had to be prepared for a zerg rush in virtually every match.