This: I can't think of a first-person shooter since Half-Life 2 which has really tried to do something original with the genre. By that I mean something which feels entirely new, and offers new experiences that you've never had before. Imagine unwrapping a loaf of bread, and slicing into it, and there's a can of Tuborg baked inside. This was Half-Life 2.
Call of Duty, Battlefield, Battlefront, even the well-received Doom reboot - they're pie-and-mash shooters wearing different hats, seemingly locked into an endless arms race to offer the biggest pyrotechnics, or the most boring and cliched story. The once-revolutionary Halo has become a shadow of its former self. Destiny is loved, but there's something about it which lacks the accessibility of a true video game great. Bioshock was great, but then Bioshock Infinite somehow flailed like an old octopus tumbling over a waterfall.
We've got all these first-person narrative games now, and games such as The Talos Principle and Portal - a sort of semi-spin-off of Half-Life - but they're not really shooters.
Half-Life 2 was a pure shoot 'em up - eschewing cut-scenes to embed its story in the gameplay - and remains potentially the most startlingly original of all time. Now get this, if you want to feel old: it was released 12 years ago.
There are many things which make Half-Life 2 an enduring classic, but the greatest of those things is this thing: the Gravity Gun. Of all the video game-related phenomena which have the initials GG, the Gravity Gun is undoubtedly the most phenomenal.
The Gravity Gun - or, more accurately, the Zero Point Energy Field Manipulator - redefined what a first-person shooter can be.
Initially, you're using it to play ball with a giant robotic dog - a subtly disguised training level - before its true potential becomes revealed.
The genius of the Gravity Gun is its versatility. On the one hand it's a weapon - and a useful fallback should you run out of regular ammo. In fact, it's so fun to use that most of us simply defaulted to it regardless.
Simply use it to lift objects from around the environment, and fling them at enemies. This can be particularly satisfying when you find flammable barrels, circular saw blades, or pots of paint (launching bombs, slicing enemies in half, or covering them in paint, respectively).
On the other hand, it also becomes a way to solve puzzles - lifting heavy objects, and making full use of the game's physics engine. Having real world physics in games is just a given nowadays. When Half-Life 2 was released it was revolutionary - and I'd argue that the way its physics are used, to present puzzles and challenges, or spring traps, remains unbeaten.
More than that though, the Gravity Gun was a way to make Half-Life 2's world feel real. It connected the player to it. Late in the game, the Gravity Gun gets a boost from dark energy, and the player becomes even more empowered - lobbing much heavier objects, such as cars, around with abandon.
What the Gravity Gun also reveals is Valve's approach to game design - how it slowly introduces new ideas, and then refuses to stay still, over the remainder of the game and Half-Life 2's subsequent mini-sequels. Its, if you will, "minquels".
The Gravity Gun continues to evolve across the game, as you use it in new ways. There's something almost Nintendo-like in the way Valve structured Half-Life 2 - and you can see the same level of design innovation at work in the company's sublime Portal and Portal 2.
It's also why it's such a crushing shame that Valve doesn't release more games, and is seemingly content to rest on its laurels/hardies with its virtual Steam corner shop. It's a massive, massive loss to gaming, and we can but speculate as to why Valve has kept its distance from continuing the series.
Too much greatness to live up to? Too much like hard work, when Steam's coffers are so stuffed with money that they don't need to do anything else? Or simply an inability to find a central gameplay device which works as well as the Gravity Gun?
Something as groundbreaking as Half-Life 2 of course had an impact on the rest of the industry. In the years which followed, physics engines were thrown around like confetti.
Some games even attempted to directly copy the Gravity Gun - see Timesplitters: Future Perfect, Doom 3, Dead Space, Bioshock - but their gravity guns (or other things - such as Bioshock's telekinesis plasmid) felt like afterthoughts, rather than integral to the gameplay.
So, helms off to Valve and the Gravity Gun - somehow, despite being 12 years old, it still feels like the future of gaming. Albeit one which has, still to this day, yet to come to pass. Weep if you must.