The Longest Journey is my favourite game. It's not the best game ever made. It's not the best-written, although it's up there. It certainly isn't the best example of an adventure game. But it's the game that most touched me – a game that literally changed my life. It changed how I think, an aspect of how my imagination works, and my philosophy. I'm not sure what higher praise could be offered.

So when the sequel arrived, six years later in 2006, I'm not sure I could have anticipated a game more. What's so fascinating about Dreamfall is how it exceeded my expectations at the same time as letting so many of them down. As a game, it's a mystery.

The Longest Journey (and you can expect spoilers for both games here, to their ends) told the story of April Ryan. An 18-year-old who found she could "shift", transitioning between a near-future of our own world, known as Stark, into an alternative reality called Arcadia.

Stark is science, technology, progress. Arcadia is magic, fantasy, imagination. They were the results of the universe being split in two in order to maintain the Balance.

One aspect that made TLJ quite so remarkable was that it turns out April Ryan is not the saviour of the universe. She believes she's going to be, she's certainly set up to think she will be, but in the end it turns out that that person is a guy called Gordon. An ignominious saving role sees him cast as the Guardian, holding the two worlds in balance for the next few thousand years, leaving April with – well – nothing to do.

Dreamfall is set 10 years later and defies every expectation. It doesn't begin with April Ryan, but rather Brian Westhouse, a relatively incidental character from the first game. Then shortly after we find ourselves in control of Zoe Castillo, a 19-year-old college drop-out living in Casablanca in 2219. Despondent, possibly depressed and certainly bored, Zoe isn't in a great place.

Having given up on her degree, and then broken off a seemingly strong relationship, she's back living with her father, moping around the house in a state of ennui, and without direction. Until the television screen in her room flickers and reveals a ghostly image of a child who frantically whispers that she must, "Find her! Save her!"

"Her", we soon learn, is April Ryan. But despite briefly taking control of the previous hero, we're back with Zoe pretty quickly, and it's with her that we spend most of the game.

That's the first way Dreamfall defies expectations. The second is to not be a point-and-click adventure.

It's instead viewed as a third-person action-adventure, but with the emphasis on the adventuring over the action. Unfortunately though, not quite enough. Because Dreamfall oh so ridiculously includes combat.

Not a great deal, and some can be avoided if you talk or sneak your way out of it, but it's there, and it's awful. No one was expecting that.

Which is a shame, because third-person is, I think, exactly where the adventure genre should have gone. It makes perfect sense. It allows much more interesting interaction, especially letting you climb, jump, etc, while still picking up objects and manipulating the world as you'd hope. Just without the flipping fighting.

And so Dreamfall goes, back and forth between brilliant ideas and absolute blunders. For every brilliant narrative idea, there's a puzzle that requires you to run back and forth through a labyrinthine set of streets over and over and over, for seemingly no reason other than to make the game last twice as long.

For every stunning piece of moving acting, there's an incidental voice that sounds like the cleaner was forced into the recording booth at gunpoint.

But this is a retrospective, so the joy is I can ignore all the crap and just talk about what I loved, and why Dreamfall is still a stunning experience, despite being an often weak game.

It begins with the main character in a coma. That's the way to start. Not a coma she then wakes up from with no memory, like every other game, but the coma from within which she's telling the story.

The first word you read on screen is the opening chapter title, "TAINTED".

Every character you encounter is thoroughly depressed.

This isn't a game that's worried about drawing in the kids. In fact, it's imbued with a strong tone of melancholy that it absolutely does not let go of throughout. This is a downbeat game, and goodness knows that's rare.

But it's not so one-dimensional as to be miserable. Within the trauma, the sadness, the directionless confusion of people's lives, is a message of extraordinary optimism, a resounding cry of hope. Because there's faith.

Dreamfall is undeniably a story about faith. It's a subject that occurs all the way through, not least in the plot of the eight-year-old girl, Faith, who is trapped between realities, haunting the future of the internet, the "Wire".

Every character is somewhere on a journey with the matter, struggling to restore it, driven by it, or utterly without it.

Zoe has lost her faith in herself. April has lost her faith in everything. Kian Alvane – a third playable character – is a man of such zealous conviction in his faith that he is blinded to the wrongness of his own actions. And Faith has simply to give up.

Shortly after the end of the first game, Stark saw the Collapse. Some sort of unexplained catastrophe that saw technology and reality break down for a few days, leading to very many deaths and a global setback.

Meanwhile, in Arcadia, at the same time a race called the Azadi defends April's new hometown of Marcuria from an attack but then occupies the city. Since then, the religious fundamentalist race has brought technology to the area, but at the expense of their fear of magic. Magical non-human creatures are rounded up and forced to live in a ghetto, often executed for their "crimes".

When we finally rejoin April, she's a freedom fighter, fighting against the Azadi occupation through terrorism. But she's not fighting out of duty, or honour, or a desire to save people. She's fighting because she hates the world and herself, and it's a direction in which she can focus her misery.

It's an extended suicide mission for a woman with no hope.

Meanwhile, there's Kian, an Azadi assassin, sent to kill April. He's a man with a conviction in his Goddess that is absolute and earnest, but completely untested.

What fascinates me most is how these faiths interact. It's Zoe's encounter with April's abject emptiness that inspires her to fight. While she is inspired by many around the world, and driven by the appeals of Faith, it's only in the face of April's refusal to fight that she sees the horror of having given up and finds her own drive.

Meanwhile, Kian is transformed through his time with April. While all April has is anger, her remarkable speech in which she explains the psychological horror of an occupation captures Kian's attention. It challenges his fundamentalism on a fundamental level.

At the end of the game, when Kian reflects his transformation back on April, it is only then that a glimmer of her own faith returns. It's an extraordinary exchange, her own ability to change others the only hope for changing herself.

Then things get a little meta as Zoe, with faith restored, has to convince the eight-year-old Faith to die. It's an allegory that resonates throughout the whole story, the only route to preventing the complete collapse of the Wire, and thus the modern world, being to let Faith die. It asks serious questions about what is left in a world when it's entirely dependent upon inert technology.

Zoe's path is one, as the opening chapter title so carefully explained, that's tainted. As much as we see this teenager regaining direction, fighting for purpose, we know that ultimately she's in a coma. A coma in which, in the final moments of the game, she dies.

Meanwhile April's story also ends in apparent death, stabbed in the stomach at the moment of her faith's reawakening, falling into a deep swamp. Kian is arrested for treason, inevitably to be executed. And Faith gives up her ghostly grip on the Wire that is causing the "Static" that would have destroyed the world, and dies.

It's of some note that this remains an optimistic game. Because, as Zoe explains at the end to her unknown audience, the job is for the person hearing the story to pick up on its themes and pass them on. It's a game about the restoration of faith, despite life or death.

It's a game about the power of story and storytelling. Zoe, in death, enters The Storytime – an unexplained place with Aboriginal Australian tones – in which she is asked to tell her story. She's a Dreamer, and her story must be told.

And despite the significant issues, it's a game with a depth of understanding of how to tell a story.

Despite the graphics having dated in the last five years, the overall look remains remarkably fresh. Which is thanks to its being a game that was directed.

A clear understanding of film technique is evident, albeit occasionally relying on some rather cheesy George Lucasy shots. But that someone had thought about the framing of a scene at all still stands out as a rare treat in gaming. Often the slow pans, carefully timed with the excellent score, are just as responsible for the emotional resonance of a scene as the writing.

As with The Longest Journey, the writing begins with perhaps a little too much cliché and misfired attempts at peppy banter. But again, as with The Longest Journey, the further you go into its 15 or so hours, the better it gets. As Dreamfall exchanges flippancy for sincerity, it creates some scenes that will stick with you forever.

Zoe's discovery of the laboratory in which Faith grew up is of particular note. A mock bedroom, packed with medical equipment, has children's drawings on the walls and toys on the floor. Zoe quite dispassionately discusses objects you ask her to look at.

But find the video file of the diary of one of the scientists, that documents Faith's final weeks as she slowly died, and a return visit to that room is bursting with sadness.

Look at the same objects and Zoe explains them with despair, horrified at how the girl had been treated, and devastated by her tragic life. Poignancy is a word so rarely associated with gaming that I didn't know how to spell it. Writer/director Ragnar Tørnquist may be a little too keen to opt for Joss Whedon's flippancy where Aaron Sorkin's sincerity would work better, but when he hits he hits hard.

And his enthusiasm for a haunting phrase of fantasy nonsense is always appealing. "The Undreaming is unchained," we're told as the credits roll. Brrrrrr. I've no idea what that means, but I'm quite certain it's terrifying.

"You belong to the Storytime," Zoe is told. There's a phrase I've been waiting my whole life for someone to say to me.

It's certainly a shame that all this is stuck in between bouts of the horrendous combat and run-and-fetch puzzles. But not enough that it shouldn't be played. Zoe's voice can be cloying, but at all the right moments it hits the tone just right. The few puzzles may be daft, and the "hacking" woefully out of place, but the message behind it all is worth hearing.

It's about faith, and why it's worth fighting for.

Before MMOs - before The Secret World, before Age of Conan and before Anarchy Online - Funcom was known for superb PC adventure game The Longest Journey.

Eurogamer cooed at Ragnar Tornquist and Funcom's creation back in 2000, awarding a massive 9/10. A less memorable 2006 sequel, Dreamfall: The Longest Journey, scored 5/10.

Now, not only has Ragnar Tornquist told Eurogamer that a continuation of The Longest Journey is possible, he's said he actively "tinkers" with it.

"95 per cent of my time is tied up - no I guess the correct answer is 120 per cent of my time is tied up with The Secret World, and I use 25 per cent of other time to work on other stuff," said Tornquist.

"I always have other ideas for the future. People always ask me about, for example, a continuation of Dreamfall: The Longest Journey, and that's something I tinker with as well.

"Right now the focus is on The Secret World; once that's out of the way we'll talk about other stuff."

Tornquist elaborated that making a new Longest Journey game is "absolutely possible".

"That's something we're discussing on a regular basis," he said. "It's just a question of finishing The Secret World and seeing where that's going and maybe I'll jump into something else.

"It would be fun to revisit [The Longest Journey] some time."

The Longest Journey followed April Ryan, a young lady of the 23rd century. She hopped between two worlds - one normal, one magical - solving puzzles and unravelling a deep story and complex plot.

Dreamfall: The Longest Journey struggled to adapt the same formula for a 3D world. The badly implemented and bolted on additions of fighting and stealth didn't help.

Video: Dreamfall: The Longest Journey.