If you believed that .Hack//Dusk would be in the same style as .Hack//Sign or even as .Hack//Liminality then you will be seriously disappointed.

The animation is pretty okay. It has nice animations, like morphing screens and such. The characters look okay too. I actually have a hard time trying not to show my personal opinion with this, since I really dislike the appearance of the characters. But I think that they look okay, if you haven't seen //Sign nor //Lim yet. Still, if you don't like childish anime, this will definitely be something you want to avoid, since most characters look really childish.

The sound is okay. The OP/END song are done by the same people who did Chobits, so it kinda sounds cute, but it's not good enough to get a good rating from me since it actually sounds like they're having some trouble singing it. The voices for the characters are okay, except for a bunch of annoying people who also have annoying voices. Shuugo is probably the worst casted voiceactor, since he keeps yelling 'Rena', but he says it with such a monotone voice that I'm seriously thinking that he didn't got paid afterwards. The voice for that character was probably the worst mistake, therefor I can't give anything better than this. Too bad they didn't stick with the //Sign music, which would be a lot better - but then again, it wouldn't fit the atmosphere here.

The story is not great. Both //Sign as //Lim start off slow, but they're building up towards a big climax, unfortunately, //Dusk tries to do the same, except it doesn't have enough story to do so. The .Hackers-legend gets passed onto two teenagers who clearly act like they haven't even passed the age to become a teenager, and that's how the story starts. Even though the appearance of characters as Balmung got my hopes up, they didn't develop the story at all, just focusing on the foolish attempts of Shuugo trying to level up with the help of some random childish characters. So there is lots of potential, but unfortunately none of it gets used, which is a real pity.
In the end the atmosphere changes to a more serious one, more darker, but that's probably even worse, since the characters look so cute and childish that one can't really look at them and imagine them in that dark scenery. Also, the ending turned out to be a very disappointing one. While you expect a true magnificent ending battle, there isn't any. And even though it kind of explains why The World started glitching and twisting, it fails to be even slightly realistic and doesn't give any satisfaction at all.

Character development is just plain crap. Shuugo changes a bit, Rena changes a bit, but to say that it's a big character development is overdone. It's hardly decent, at max.
I got seriously annoyed by Shuugo yelling 'Rena' all the time, since the voiceactor didn't gave any feeling with those yells. Also, even though Rena and Shuugo are supposedly teenagers (around 12-14 iirc), they act like they're not even 10 years old. Another annoying person was that classmate, who tries to speak French. He's definitely brought in to make this anime funny, but he only succeeds in annoying me.
Balmung was an interesting character though, and he changes quite a bit as well. I would've liked to see a //Sign series which featured him.
All other characters don't change at all. They get introduced and they play their parts, but other than Kamui and Reki none of them actually develops at all. It's as if they're just added to spice up the series, but nobody knew what to do with them, which is a real waste, since some of them had some potential, like the WolfGirl (she had such an big role that I don't even remember her name, 10 minutes after watching the last 5 episodes) or Sanjiroh (or something).

I don't really know if this is worth rewatching for anyone, but I certainly won't. I kept getting more and more annoyed, especially because of Shuugo. His voiceactor was really bad, and most of the characters were annoying as well. After having seen //Sign and //Liminality I expected a nice series which would somehow look like the other two, but this is just a kiddy anime which doesn't even slightly resemble the world I liked. I don't mind childish anime; I liked Angelic Layer, and I kinda liked Dragon Drive, but //Dusk is meant for even younger children, and that's what I didn't like.
The comedy in //Dusk is mainly Shuugo falling in the water, walking with his head to a tree and more of that stuff, and that's what 5 year
old children would laugh about, but nobody else.

Personally I wonder why they created //sign as an introduction of The World, not finishing the entire storyline (but it was decently finished), followed by //Liminality, about how everything in The World had its effects on the real world, and concluding it with //Dusk. Now you can say that none of them are really related except for 'The World', but you cannot create anentire world, introduce a problem and not finishing the story. //Dusk was nothing more than making a kiddy anime in order to deal the final blow, as if they really wanted to get rid of the whole concept.

For me, even without realizing it was a 'The World' anime, it utterly failed to capture my interest.