Those sex cards, eh? I was determined to collect as many of them as I could. If that meant going out of my way to safely escort a barmaid home late at night, so be it. Convincing a dryad that sex is not just for procreation, that it's fun and can relieve stress? No problem. I couldn't help myself. It was like sexy Pokémon.

The Witcher's anthropological commentary on humans' slavish obedience to their base, animalistic instincts, to the detriment of the greater good, was intelligent and incisive. Or at least it would have been if that's what the sex cards represented. Realistically though, they were purely for titillation.

Irrespective of the heavy-handed way developer CD Projekt RED implemented erotica in The Witcher (a concept the studio didn't so much flirt with as take it to an abandoned mill and indelicately shag senseless), its inclusion was representative of the core elements of characterisation that run through a game influenced by the short stories of Andrzej Sapkowsk, which tell of the infamous Geralt of Rivia, the 'White Wolf', a monster-slaying mercenary known as a 'Witcher'.

The game plumbs the ethos of these short stories to add definition and weight to the world and its characters. These are people with histories. Some share a personal history with Geralt, though none are probed in too much detail. Nor are you beaten over the head with endless conversation trees, because the developer attempts to shoehorn the origins of each relationship into the tale of the amnesiac White Wolf.

The amnesia mechanic is a little unfortunate – a clumsy way to explain why it is that you play Geralt as a 'level 1' Witcher rather than the famed monster-slayer that everyone else seems to know him as. It's especially clumsy as much of Geralt's skill progression is based on combat prowess that you imagine would be so ingrained in him as to be second nature.

The stripping away of abilities and powers is the eternal conundrum for games that tell you you're a fully-formed powerhouse but still need to leave room for progression. CD Projekt RED wisely chooses not to make too much of a song and dance of it. You're Geralt of Rivia, you have amnesia for a reason that is never fully explained. Now get on with it.

Being assigned the role of Geralt, amnesiac or not, enables some smart narrative twists based on the choices you make guided by Geralt's ambiguous moral compass. You are not some abandoned child or lowly commoner destined for great things, one who starts with a blank slate to be written and a forehead size, degree of overbite and hair colour decided upon by random tugs on a sliding scale. Here you play Geralt of Rivia, Witcher, professional monster-slayer, gambler, womaniser, drinker and, frankly, a bit of a hard nut.

He also has his bad points. He doesn't seem to know how to stand naturally during a conversation, for one thing. Despite CD Projekt RED's love for its first game being plain to see in other areas, you sometimes have to squint and turn your head sideways to see past the ugly. The dark fantasy art direction is sufficiently bleak, gothic and full of character and, granted, Geralt's movement in combat is fluid enough, with cuts, thrusts and balletic twirls to reward the well-timed mouse clicks that facilitate the combo system. But during conversation the characters appear beholden to an incompetent puppet master.

The 'Enhanced Edition', released almost a year after the original, went some way toward rectifying this, introducing extra animations and NPC models alongside other welcome touches such as an overhaul of the inventory system to separate and sort the numerous alchemy ingredients. The developers also made a significant gesture of removing digital rights management altogether, resulting in no install limits and no disk check. Furthermore, it packaged all of the extras up as a free download for those who had already bought the game.

On returning to the game now, it's the stories within stories that impress most. Those narrative mini-arcs that show the game's tagline to be more than idle boast: "There is no good, no evil – Only decisions and consequences." There's the expected branching storyline, but with very little of the blatant good vs. evil choices that are so clearly signposted in other RPGs. As long as you choose the path that is best suited to how you're playing Geralt, rather than that which you estimate will net you the most loot, you're never made to feel that you've made 'wrong' choice.

Consequences play out as mini cut-scenes in the style of hand-painted storyboards, with Geralt providing a voiceover explaining that the events of right now are transpiring because of the decision that you made, in some cases, several hours previously (there's no quick-loading in order to pick the other choice).

The decision that stuck with me most came on my first playthrough. Having journeyed to an out-of-the-way swamp and completed several of the local quests, I had to choose one side in a conflict: the rebel force or the authoritarian soldiers. Neither side is explicitly good or evil, and you can see the point of view of both.

The rebels are made up of the non-human races (elves, dwarves and the like) and are victims of racism. They've been forced from their homes to live on the edge of poverty. With barely enough food and water for their families, they have taken to obtaining these things by force, which in some cases has led to innocent humans being caught up in the fighting between them and the authorities. You can see the persecution and, in most cases, it would be simple enough to side with them to fight against the 'evil' empire that imposes such oppression.

Except that here the empire isn't evil, and nor is it even your enemy. From the soldier's point of view, the rebels are effectively terrorists and it's not them forcing the suppression on non-humans, but society as a whole. Though the authorities are doing nothing to redress the balance, their interest is in keeping the peace and stopping any further attacks by the rebels.

So do you lead the imperial unit to the rebel camp to rout them completely, or do you lead the rebels in a pre-emptive ambush on the imperial guards camped in the forest? I felt that as a Witcher I should remain impartial and not get involved in the politics, so I continued to go about my business, determined not to help either, although it seemed that neither would attack the other until I acted and both would be stuck in their respective camps for game-time eternity. Eventually I left the swamplands, willing to leave that particular branch of the story unresolved, such was my feeling for remaining true to the neutrality of the Witcher ethos.

But it did resolve. Despite what seems like a two-choice scenario, CD Projekt RED built in an invisible third choice: do nothing, as I had. This choice comes with its own outcomes and pretty storyboards further down the line, and you're chided for your neutrality; reminded that it has its own consequences. Had I created my own character, I likely would have chosen one side over the other, but with The Witcher I felt it was my duty not to choose, because that was what a Witcher would do.

The Witcher's legacy to me is that it encouraged me to play an actual role, rather than flesh out a cipher with a range of canned goods and evils. It illustrated that game developers needn't rely on reward or punishment to make us care about the choices we make: provide compelling narrative, not shiny trinkets, as the preeminent consequence of our decisions and that will be enough. We'll even forgive you the sex cards.