First, I'll give you something Dark Souls never does: a warning. Brought to PC by From Software, this port of the Japanese fight-heavy action-RPG is just that: a port. A straight port.

It plays like someone took an Xbox 360, packaged it up small, and slid it into your PC when you weren't looking. The HUD is huge, the textures muddy, and such luxuries as control over field of view and vsync are nonexistent.

Ask yourself how you pronounce 'PC game'. If your emphasis is on the 'PC', then run. Run far from Dark Souls and don't look back. There is nothing for you here.

There are many reasons to run. The twisted, shrouded, uneasy medieval fantasy land of Lordran stretches away like the darkest night. Go the wrong way, probe too deeply into the inky depths, and the things that lurk there will get you.

My best analogy: it reminds me of being six years old and hearing a noise downstairs in a dark house.

Dark Souls starts you off, no matter your character class, as a walking corpse in a purgatorial prison, clutching a broken blade. In front of you is darkness.

I get out of bed to discover the source of the noise. In front of me is darkness.

Each step I take elicits rising fear, and rising courage. I can do this. Do I want to do this? I find a sword on the floor. I equip it, and my character weighs it reverentially in her right hand. I find a plastic squeaky hammer on the landing. I pick it up.

Trudging up the stone steps.

Padding down the carpeted stairs.

More darkness. Creeping around a corner, sucking in a breath through clenched teeth. And there it is: the source of the sound, the reason I'm probing the unknown.

A bowl the juddering washing machine knocked into the sink.

A twenty-foot demon with stubby wings and a hammer longer than my character is tall.

Either way, I know my enemy.

Playing as a walking, conscious member of the undead, I was tasked with battling my way out of my prison. On my escape – by medium of giant crow – the game took me to darkened land of Lordran. My job: to bring light to the world, and to fight for my soul.

All players start the game 'hollow'. Collect 'humanity' – little sprites scattered around the game – and clench it between your fingers, and you'll become human again for a while, injecting colour into your pinched, rotting cheeks – until the next time you die. I fought for these moments, moments that differentiated my character class from the drained and undead creatures stalking the darkness around me. Die, and when you respawn, back at one of the scattered bonfires that serve as safe havens, you look like a monster again.

Dark Souls' first demon lived behind a door. When that door closed behind me, I was obliged to fight something that could crush my puny body with a swing of its ludicrous hammer, that could flutter a short way into the air and squash me with its bulbous arse. Something truly horrible, just like I'd imagined was downstairs in the dark when I was six years old.

Another warning: Dark Souls feels unfair. This demon was nine or ten times my bulk. If I swung my mace, I might chip 28 points from his enormous health bar; if he swung his, he was capable of hacking off more than half of mine.

Some players will give in to the fear – understandably so, when the dark is only partially explored and already hides such terrors – and call for their parents.

I died the first time. I think everyone dies the first time. I was flung backward into stone columns that crumbled under the force.

Dark Souls' combat has a weighty physicality to it: monstrously powerful foes can smash through all but the strongest shields, and different weapons feel markedly different in use. Spears are jabbed from behind shields, puncturing enemies with an audible pop. Clubs and maces feel heavy and powerful when brought down on heads – especially with a character's heavy attack (mapped to right-mouse or R2 on a pad). Bows are quick to fire if you have high enough dexterity, daggers can be stabbed into exposed backs for devastatingly powerful and wet-sounding critical hits. Dark Souls' combat is brutal, tactile, and always tense.

Stumbling to my feet, I raised my shield, but for nothing. My stamina bar was too low, my grip too weak. The demon's weapon collided with my character's frame and Dark Souls' favourite words flashed up on the screen: “YOU DIED.”

Throw your hands up, walk away. How are you ever meant to beat that? With these dodgy keyboard controls that almost necessitate the use of a controller? No one can beat that thing, it's too tough, it's unfair. I'm going back to bed.

I don't blame you. That feeling never goes away. Fifteen hours into Dark Souls, I fought a ten-foot bipedal goat man. He was armed with two vast cleavers, and supported by two vicious dogs. Raising my shield, I could deflect the goat demon's blows, but staccato bites from his mutts raised my poison gauge to critical levels. Swinging my mace in a wide arc, I crushed the skulls of the dogs, but I was poisoned, losing health as I was backed into a corner. The goat demon reared back to strike. I darted between his legs, aimed a blow at his heel, and promptly keeled over, dead from the dog's venom. YOU DIED. This is bullshit, I'm turning this off.

I did. And then 20 minutes later, I came back. If I'd rolled forward immediately on entering the goat demon's lair, maybe I could kill the dogs before they could bite me. If I manipulated Dark Souls' responsive combat system well enough, maybe I could triumph in the dark.

I died again. Ah, this is bullshit. One more go. I'm six years old and I've heard the noise. I can't go back to sleep. I can't stop thinking about it.

I've finished Dark Souls twice now, and I still can't stop thinking about it. Remember what I said in my first warning, about the pronunciation of 'PC game'? That wasn't entirely true. Dark Souls' port remains poor – and it uses Games for Windows Live, perhaps the biggest demon of all – but in all other respects, it's a game with a natural home on the PC. I've compared reams of stats. I've planned my character build. I've ground out the game's currency – souls from vanquished enemies – in favourable spots. I even worked out the best weapon to scale with dexterity, and killed strange-limbed shells in a giant underground lake for four, five hours at a time just so I could upgrade my Titanite Catch Pole +3 to a Titanite Catch Pole +4. It's a game that tailors beautifully to the kind of glorious obsession we're the kings and queens of on PC.

When I first played Dark Souls on console, I discussed my characters with friends. As a Hunter, I rolled away from combat, my bow in a two-handed grip that left no room for my shield. A friend never left the safety of the bonfires without his: a six-foot stone shield, tall enough to hide his Warrior character behind and tough enough to absorb all damage thrown at it. There's camaraderie in these inevitable discussions: kids meeting on the landing, psyching themselves up to make the trek into the unknown, judging different approaches. Scream forward into the gloom and bash whatever it is with a stick? Sure, might work, but I'll hang further back and bide my time before launching my assault, thanks.

Dark Souls is a game entirely about combat tactics, and it succeeds in making a vast range of them viable. As well as my Hunter and my friend's sword-and-board Warrior, I've seen spell-spouting Sorcerers and Assassins so quick they can parry (left trigger on the 360 pad, timed perfectly against a foe's strike) every incoming attack, opening a window for a lethal critical hit. There's real choice in the way you can battle your way through the game, as well as choice in the kit you can do it in. Your starting gear, once levelled up with the right equipment – dropped by certain foes – is competitive with gear found much later in the game. There's no set alpha-tier equipment, simply what suits a player's style – be it play-style or aesthetic style. My Cleric wore a skirt and leather boots for the manoeuvrability bonus it offered her; my Hunter dressed as Death himself with an oversized black cloak hiding his face for the confidence boost it provided me.

There's a similar range of choice in exploring the game-world. Like my dark, clanking house, the realm of Lordran – and later Anor Londo – seemed to open up beneath me. No corner of this world is inviting, but almost all of it is open to exploration in any order.

There is a suggested route: first high through the medieval, European-looking Undead Burg, to ring the first of two bells, then down into the Darkroot Garden with its faceless tree-men. But with enough skill and foresight, players can avoid these places and go deeper into the Earth. The New Londo Ruins are flooded and infested with phantoms. Deeper still, it's inky black. I found twisted ogre men and evil gelatinous blobs, manifestations of childhood nightmares. Even further, seemingly miles below the game's grey steel sky, I found the Abyss. I won't tell you what's down there.

The world, like my remembered childhood house, is always dark. It's also connected. Playing Dark Souls is to draw a mental map, a little mnemonic of connected spaces.

Lordran feels like a place. A place infested with horrific nightmare creatures and Cthulhu's baby brothers, but a huge place in a way few games have ever achieved.

It's a place I spent most of my time alone in. Just as creeping into the dark as a six year old is a profoundly lonely experience, so it is here. Dark Souls' most enduring characteristic is its difficulty, but that's only one view of the game. Think of it this way instead: where every other game puts the player on a glorious pedestal, Dark Souls simply doesn't care about you. Until the end of the game, the very first enemy you encounter can – if ignored – chop off most of your health bar in a few swipes. There's no special treatment, no basecamp radioing in to check on your progress, no comforting voice in the darkness... bar your own, whispering “come on, I can do this.”

Well. There's no one else most of the time, anyway.

Sometimes, you're not alone. Black Phantoms are Dark Souls' alpha bogeymen, the red eyes in the dark that want to eat your skin and chew your bones. They're Dark Souls' most dangerous foes, and they're human. Other players can invade your game – over the rightfully hated Games for Windows Live – and attempt to kill you for profit or their own pleasure. If you're unlucky enough for one to crack its way into your game, you're furnished with one of Dark Souls' few warnings. From there on, you're on your own.

Black Phantom duels are Dark Souls' tight combat system at its best. A lock-on option enables nervy circling before the fight-proper starts. When it does, the best players use geography and height as much as sword-swings and shield blocks. Lure someone close to the edge of a cliff, then hit forward and light-attack to kick them off it. These fights are always fantastic.

Dark Souls' novel online system has more benign versions of the Black Phantoms, too. Blue Phantoms are for co-op play – but don't expect to be able to jump into a friend's game. The people at From Software have a strange vision of online gaming: I spent hours waiting for some random person to summon me to their game. The less altruistic might not bother – especially when Games for Windows Live is such an effective turn-off.

And it's how much you let GfWL – and the game's direct-from-console port – affect your experience that determines whether you'll make the trip down those dark stairs. This game isn't buggy, doesn't crash, and loading times are quicker than they were on console, but you won't find the things you should rightfully demand as a PC gamer here: there are few graphical options and the game is locked at 30 frames per second. For a game this good, I don't think that matters.

If you know the trip downstairs will be long, hard, and sometimes uncomfortable, but you want to take it anyway because you know it will reward you like nothing else – if that noise downstairs leaves you too curious to climb back into bed and cover your ears – then Dark Souls: Prepare to Die Edition is waiting for you at the bottom of the stairs. I suggest you go and investigate.

(Note: A few hours after the game's launch on Steam, dedicated hero-type Durante knocked together a patch that unlocked the game from its 720p shackles, and allows it to run in proper PC resolutions. Get it from Neogaf . Thanks to Eurogamer for the spot.)