It is the biggest movie of the season, a martial-arts fantasy set in Purgatory called THE RESTLESS (or “Jungcheon” in Korean, a Purgatory-like world between heaven and hell). It is the story of a warrior (Jung Woo-sung, of DAISY, MUSA, and lots of stuff) who travels to Jungcheon to look for his lost love (Kim Tae-hee, mostly from TV, like LOVE STORY IN HARVARD). He finds her, but she is now an angel and does not remember him. But when an evil force threatens, Jung must save his love and the rest of Jungcheon.
THE RESTLESS is 10 billion won ($11 million) and looks like it. Heck, it looks like 20 billion or so. This is a gorgeous spectacle of a movie, with (mostly) first-rate special effects, lavish costumes and huge sets.
Unfortunately, the story does not measure up to to amazing production values. The story feels like a cross between A CHINESE GHOST STORY and LORD OF THE RINGS (does anyone really need a link for this?). Ghost Story because of the fantasy and cheesiness. Lord of the Rings because of the epic scope and general spectacle. 
The action in THE RESTLESS is pretty good. Full of special effects, the characters fly around with a lot of flair and weight (so often, f/x people look way too light and fake, but when the bad guys land in this film, they really crunch the ground… a detail I quite liked). A couple of baddies have this cool Doc Octopus thing going on which looked great.
Unfortunately, when the action ends, the film comes screeching to a halt. The contrast was really stunning. One moment, you are rocketing around at 100mph, then next moment you are in park. Considering how BICHEONMU, SHADOWLESS SWORD and MUSA also had the same problem, it seems to me to be a structural problem of some sort. (If you want to see the exact opposite, watch the DVD of PIRATES OF THE CARIBBEAN and check out the screenwriters’ commentary… lots of interesting stuff about how to embed information without turning a movie into boring exposition).
Also like Musa, Bicheonmu and Shadowless Sword, THE RESTLESS is unrelentingly humorless. Not a smile to be found. Especially in a film so over-the-top. We are in purgatory, after all… Nothing wrong with having a cheesy story, but you might as well have some fun with it.
Not a whole lot of subtlety going on either. Good is good, bad is really bad, motivations are cliched. 
As for the acting… it is about what you would expect. Jung is solid, as usual. Kim Tae-hee, however, seems to have gotten acting lessons from Kim Hee-sun.
Another complaint is one I have with almost all superpower films, and that is watching the characters’ super powers expand and contract from scene to scene. We know that these characters can fly, so why are we watching them running along the ground in a chase scene? But I had the same problem with the Superman and Spider-Man movies.
So, to sum up… If you are looking for some great eye candy and a bunch of action (and don’t mind a few dull stretches), THE RESTLESS could make you pretty happy. Just don’t expect much more than that.
UPDATE: Well, looks like there was a good reason that the costumes looked so good in THE RESTLESS. The costume designer was none other than Emi WADA, a woman who has designed outfits for some first-rate films, including Zhang Yimou’s HOUSE OF FLYING DAGGERS, Peter Greenaway’s PROSPERO’S BOOKS (great film) and 8 1/2 WOMEN, and for Akira Kurosawa’s DREAM and RAN (for which she won an Academy Award).
I love the beginning but it seems the movie dragged on a bit in the middle. There are some stuffs that doesn’t make sense too. How did the gang managed to avoid memories being erased first? (I guess that they refused to go to the hot spring..) How did Yi Gwak rocks now but was bullied by mere village people? (He is such a fast learner?) Also the white guys sucks! They were the guardian of the place and got their butt kicked by a gang of 5 who got their butt kicked by a bunch of low-level palace guard in life. At least they should bring the plot more interesting by having some really strong white guard deemed Yi-Gwak was a spy as well Yon-Hwa as a traitor and chase after them. Why does the gang of 5 gain such strong inhuman power but most white guards just as bad as normal human soldier?
Introducing the musician guy in the middle to explain the goodness of remembering things is a good thing to help people understand their world better. But a total fruity guy is not necessary. I feel sympathy towards the brothers. They were just doing their job. The red girl role served some purpose but not a lot. I don’t know why but I tend to compare this movie alot to another movie called “The Shadowless Sword”. Even the plots are totally diff but it is all about protecting someone from a bunch of bad guys.
Effects are cool. I love the how when someone died they turn to ashes (btw I guess there is no flesh wound in this world.. you get a cut you died like those vampires in Blades). Fighting scenes are so so. I have seen better fighting scenes in Korean movies (Duelist). Good thing is I see the plot is pretty original … at least I can’t find an identical plot movie (some kinda close to it but not as close as comparing Puzzle to The Usual Suspect).
Personally I give it a 7/10. At least I enjoy it a lot more than The Host. I will definitely re-watch it if I get a chance.