Half-Life, now there's a blast from the past. I've played the first one, but couldn't muster enough interest to finish the second. And I think that's because the first did something new, it shook up the genre and, I'll explain this later, it really showed off the latest tech.
Back then you had shooters like Doom, Quake, Duke Nukem 3D. All great games in their own respect. Yet these games have no story to speak of and weren't having any pretensions in that regard either. The story was there to point you towards the baddies, and you, playing mister Blaskowitz, are the man for the job. They were all about good gory fun.
Half-Life had you start out as a research assistant, a geek, riding to work on the monorail, performing several menial tasks. This served both as a prelude of things to come as well as a very smart tutorial which allowed the player to accustom himself to the controls. Immersion, a nowadays filthy buzzword from the mid 2000's comes to mind, yet it perfectly describes what Half-Life did back then. It sucked you in to the story and didn't let go before you saw the ending credits.
As for the tech... In those days you had 3d accelerator cards (3Dfx). Cards that required an additional PCI-slot, that couldn't operate on themselves (you still needed a separate VGA card) and on top of that cost about half the price of your whole rig. Yet Half-Life showed why it was worth the investment. Or at least you could justify to your self spending all that money by showing off to your friends. Perfectly smoothed edges, fluent gameplay, games couldn't get any more realistic than this. Or so I thought back then, of course the game is a fossil (albeit with very smooth edges) compared to today's graphics.
So there you have it. A revolutionary game with ditto graphics that was released at exactly the right time. If you haven't played it yet, I'm curious to hear if it held any appeal to you. I'm afraid not actually, everything the game did right back then has been done better by countless other games today.