There are no collectibles in Half-Life. It’s incredible.

That’s not how I would have praised the groundbreaking first-person shooter, which turns 20 years old today, when I first played it. At that point, I might have described how Half-Life infused sci-fi shooters with a sense of realism. It set an alien invasion in an Earthbound scientific research facility called Black Mesa, where an ordinary man (or at least, an ordinary MIT-trained theoretical physicist) named Gordon Freeman is forced to fight for his life — but he can also mess with a fellow scientist’s microwave lunch. I might have discussed its immersive storytelling, which never pulled players out of their first-person perspective. I probably would have referenced the distinctive opening level, which introduces players to Black Mesa with a five-minute tram ride.

Half-Life helped define a generation of first-person shooters. And because of that, many of its original innovations are now taken for granted. (The Half-Life manual, for example, boasts that you’ll find weapons in “realistic locations” instead of spinning in midair.) So in 2018, what stands out are the elements that modern video games have left behind — sometimes for good reason, but often in ways that make Half-Life feel impossibly elegant.

By modern standards, Half-Life fails to clear basically any bar that we’ve set for a big-budget game. Its levels are relentlessly scripted and linear, with occasional semi-secret areas. You can’t modify weapons, upgrade gear, or craft supplies. You probably won’t form meaningful relationships with side characters since you’ll rarely interact with one for more than a minute. In a year where critics lauded God of War for humanizing the formerly one-dimensional killing machine Kratos, it’s more obvious than ever that Gordon Freeman is a cipher with a crowbar. We don’t even know why he’s so good at wielding it!

It’s a game that rewards achievement, not completionism

But the result is something that feels urgent and purposeful, rewarding achievement instead of completionism. Before I booted up Half-Life again last week, I hadn’t realized how much I’ve come to take grinding, scavenging, and aimless wandering for granted, even when I’m supposedly chasing a crazed cultist or a league of supervillains.

There’s a lot of endearingly funny unrealism in Half-Life, like the five character models that stand in for Black Mesa’s entire staff, the bizarrely indestructible doors that force players into long and dangerous detours, and the obligatory level where enemies lock you in a poorly secured prison and take all your stuff. But its stripped-down design and tightly managed pacing are a perfect match for the story. The game nudges you into constantly advancing, doing virtually nothing beyond what helps you stay alive.

Valve is masterful at creating the illusion that you’re finding some clever route around a problem, despite that being clearly the only option available. Even the hidden paths, including one that lets you skip an entire level, are accessible in ways a man who’s desperately trying to escape might try. I might not know Gordon Freeman, but I know that we want the same thing: to get out of Black Mesa as quickly as possible, audio logs and crafting material be damned.

Few shooters were ever as ambitious and economically designed as Half-Life, but the game stands out more than ever now because the linear, story-driven, single-player shooter hasn’t been a cultural force for years. Rock Paper Shotgun writer John Walker has argued that Half-Life’s bombastic 2004 sequel killed the genre, driving developers into a death spiral of ever-costlier cinematic set pieces. But Half-Life’s formula simply had very clear limits. The game wasn’t self-serious or plot-heavy; its narrative amounts to Gordon Freeman fighting successively bigger monsters. Even so, it helped make first-person shooters the default vehicle for “serious” narrative games, and the more ambitious these stories got, the more absurd and restrictive their language of ceaseless, mandatory violence became.

Half-Life 2 knowingly winked at this fact. It brought back similar mechanics, but with a plot that made Gordon an unwilling pawn manipulated by an otherworldly force. Other characters began pointing out that despite being a supposedly brilliant scientist, he can’t do anything except flip switches and kill aliens. “You have destroyed so much,” laments the game’s antagonist at one point. “What is it, exactly, that you have created? Can you name even one thing? I thought not.” The speech is transparently self-serving, but it’s not wrong.

‘Half-Life’ helped make story-driven first-person shooters obsolete

And after that, linear first-person shooters virtually deconstructed themselves out of existence. BioShock used mind control as a metaphor for players’ lack of free will, starting with a reference to Half-Life’s famous crowbar. Spec Ops: The Line turned cliché military combat into a nightmare that effectively berated you for choosing to play it. Meanwhile, Valve’s level editor let indie modders build first-person shooters without the guns, resulting in walking games like Dear Esther and The Stanley Parable, which offered the same (or greater) storytelling potential without the need to explain why you were constantly killing people. Half-Life is a wonderful game about a silent man on a narrow path with a deadly arsenal. But you can only tell so many stories that way.

Series fans have awaited a rebirth of the Half-Life series, which ended on an unbearable cliffhanger in Half-Life 2: Episode 2. But the mythical Half-Life 3 is almost certainly dead, and long-departed series writer Marc Laidlaw has posted its plot online. There are rumors of Valve making a prequel for a new virtual reality headset, but given how long it’s been since Valve released a single-player game (and how quickly VR projects can crash and burn) the odds don’t favor it.

While I doubt we’ll ever get an end to Gordon Freeman’s story at this point, the original Half-Life somehow still feels novel, even as it’s comfortingly familiar. Valve built a series on making sure that players kept moving forward — but sometimes, it’s better to look back.