I knew Horizon Zero Dawn was going to be visually impressive. I knew it was going to be huge, filled with robots and gear upgrades and quests, and I knew that at the very least it had the markings of a game with something interesting to say. But I didn't expect this.

Horizon has all those things but it also has heart. It goes places I never could have expected, and that's true in an epistemological sense, in a philosophical and an emotional sense as well as in terms of the places protagonist Aloy literally adventures to.

This is a special game, one which puts forth a very confident spin on action-RPG conventions and on the idea of a post-apocalyptic survival tale, but also one that will engross you in its mystery and poke at common humanistic ideas from an angle we don't see a whole lot. That said, it certainly doesn't hurt that it's amazing to look at and has heaps of cool robots to blow up, and its actual game mechanics are just as engaging as the story it tells.

The game takes place 1000 years after some sort of global catastrophe has all-but wiped out human civilisation, and the people that are left live in tribes that resemble the primitive peoples of our own past. While these people live off a land retaken by nature — filled with tangled jungles, wild animals and rushing waterways — they also live alongside beast-like machines, and accept them as another natural part of the world.

Aloy grew up as an outcast of the Nora tribe, a technology-fearing society that forbids interaction with the ruins of the ancient humans. On a quest to discover why she was so shunned, and who her birth mother was, Aloy discovers that the world is quite different outside the Nora Sacred Land, and finds her answers are tied up in a number of greater mysteries: what happened to bring ruin to the ancient humans, and what is the true nature of the wild machines and their creation?

I was hooked on the mystery from the outset, as early in the game a young Aloy enters an ancient ruin and finds a mysterious device. Recognisable to us as a kind of augmented reality data assistant, the device gives Aloy a unique insight into the old world, showing her the true nature of the technology around her that the Nora regard as divine or evil.

For Aloy this is a source of perspective and knowledge, and also an invaluable aid to her survival (it can, for example, calculate the routes of enemies and detect their weak points, even through walls). But to us as players it's a window into our future and the world of Horizon's past, which we can experience through audio, written and holographic logs.

The game gives a dose of this early with several accounts of humans' last thoughts on the eve of their destruction — as well as a heartstring-tugging holographic message from a father who couldn't be there for his son's birthday — and while learning about the ancient humans is never quite as central to the story as learning about the machines and the circumstances of Aloy's birth, it's worth going off the beaten track to find every bit of well-written information you can get.

Aloy herself is a great cypher through which to see the world. Virtuous but determined, she has enough knowledge to separate her from the pious Nora but is still as naive as we are to the ways of the wider world. Though players are able to guide her actions and her responses in conversation, in most cases they'll only be choosing which aspects of Aloy's personality to put forward most strongly: her wisdom, her empathy or her physical ability to dominate.

Mechanically, Horizon is remarkably fluid and the game experience is likely to differ from person to person. At a basic level you can either play stealthily — availing yourself of long grass to remain hidden and wait for your chance to strike — or aggressively. Either way the controls let you transition easily between sprinting, climbing, dodging, sliding, jumping and attacking in a way that suits perfectly the overall cinematic presentation. Once you get good at Horizon's combat — a feat which also involves getting to know your traps, equipment and various gigantic robot enemies — every encounter is an acrobatic action movie.

From there you can further augment your playstyle by choosing which skills to develop and which weapons, gear and outfits you'll turn all your found loot into. I'm always a sucker for collecting outfits in games, but I especially love the mix of sci-fi and cavepeople chic in Horizon, with cables and hard casing from fallen robots standing in for leather and bones on the Nora outfits. More exotic options become available as you meet craftspeople from other tribes, and each customisable garment has specific strengths so you'll be swapping to suit the situation rather than just upgrading every now and then.

The entire system encourages you to be constantly collecting, upgrading and improving — between, of course, taking quests from people in the world and solving the core mysteries — but it does it in a way that's rarely annoying. A good example is that if you have your eye on an outfit or weapon but don't have the parts, you can turn it into a quest at the press of a button. The game automatically sends you off to the places you need to go for your resources.

Finally, the game quite simply has some of the most picturesque landscapes and evocative locations ever seen in a video game, with just enough of the fantastical coming through in the robot designs and technological elements to offset the gritty realism of the people and places. There's a Photo Mode included in the game so you can compose and share your own snapshots, and for good reason. From desert to underground ruin and from sun-rise to the light of the silvery moon it all looks immaculate.

As well as the purely aesthetic, every moment in the game is filled with little functional touches. Like the fact that fireflies crowd in the long grass after dark to make it easier for you to see where you can hide. Or the fact that Aloy chatters humorously to herself as a way of commenting on your playstyle.

From its bows and arrows and primitive guns to its day-night cycle and echoes of an ancient past, Horizon doesn't necessarily do anything you haven't seen before. It just does it all extremely well, and with a sense of cohesion that not many games this large can pull off.

Horizon Zero Dawn is out for PlayStation 4 on Wednesday March 1.