Let me start by telling you the faults of the game, just to get them out of them way, and make room for what's great about it. The combat sucks. There's just no way around it. Fortunately, there is very little of it. Future games might want to take a hint or two from Indigo Prophecy (aka Fahrenheit), and just have quick time based fighting or something. This is an adventure game, afterall, and it should stay purely adventure, as there is no room for anything else.
What's great - the story. It is completely mind-blowing. I don't mean that as a cliche, but literally mind-blowing, because it will really make you think - about life, about purpose, about reality. The game touches on themes from Indigenous Australian mythology, and does so brilliantly, adding a new dimension to the twin-world lore of the Longest Journey franchise - dreams being the common thread that connects the two worlds, and also their origin. Without getting too much into the philosophy of Dreamfall, let me just say that if for no other reason, then you must play this game for the story. Decidedly mature, but never gratuitous, and blurring the boundary between fantasy and science fiction, Dreamfall's narrative would be screen worthy, but for the fact that it is too large to be contained in a single film, and would probably be butchered on television. So the interactive medium was the correct choice to tell this story.
Kian is a man of both unshakable faith and honor. He has committed himself to the word of his Goddess, which he believes is aligned with the will of the Six Empresses of his kingdom, a belief that is easily protected within his home city, insulated from the reality of the outside world. Once abroad, however, and faced with the grim truth of what his Empire does in the name of the Goddess, he questions not his faith, but the politics of his leaders. It is a strange sort of thing to play as a character who is killing the allies of another of the playable characters and watching as he comes to grips with his purpose.
Zoe. Zoe, Zoe, Zoe. There is so much to say about the new main character - but in a few words, she is a dreamer who has lost the ability to dream. Like the other characters she questions her purpose in life, and has become restless, lazy, uninspired, and bored. So when her closest friend goes missing, she jumps at the opportunity to search for him, not out of some altruistic instinct, but out of a personal desire to rekindle her sense of purpose. Along the way she discovers that she is tied into the very nature of the twin worlds, that she has some affinity to the Dreaming.
Although most of the game is played as Zoe, there is enough of April and Kian to add plenty of variety and alternate perspectives, creating a truly three-dimensional narrative.
Dreamfall is probably better described as an interactive story than a video game, and so a warning to action gamers and even RPG-players, this is a game purely driven by its plot and characters, with everything else merely an excuse to keep you involved. For me and other adventure game lovers, it is perhaps the crowning achievement of the genre, an example of how a video game can be art - indeed, interactive literature.
Of lesser importance to the overall product, but worth mentioning is that the visuals are excellent - not the high poly count of current gen games, but rendered in a style that somehow allows it to remain timeless. Clean, simple character models with no muddy textures, and gorgeous environments that showcase top-notch art direction. From the bright and clean quasi-futuristic middle-eastern look of Casablanca to the esoteric and hauntingly beautiful City of the Dark People, there is plenty to look at in Dreamfall. The only shortcoming here is that the environments aren't larger, because here is truly a world that you'd like to spend a few hours just exploring.
As for sound - the music is mostly ambient, and falls into the background, present enough to create an atmosphere, peaking at critical story points, but never intrusive. Of greater importance is the quality of the voice acting, which does justice (at least in English) to an incredible script. The believability of the characters is enhanced not only by what they say, but HOW they say it.
There is so much to love about this game, I could spend another ten paragraphs singing its praises, but I'll spare you. Let me just summarize it all by saying that this is the single greatest adventure game that I have ever played, and a contender for my favorite game of all time. If you do not agree after your first playthrough, I'd recommend waiting awhile and giving it another go, perhaps after dabbling in a little of the underlying mythology.
I give Dreamfall my highest recommendation.