If only more horror movies had a similar vibe to this flick. It's not about big jumpy "BOO!" scares and loud crashing noises on the soundtrack. It's about a creeping sense of dread in an intimidating atmosphere, and while it's not going to freak out horror fiends such as myself, it was a far more convincing slice of genre fare than - for example - The Haunting In Conneticut, which was a case of loud noises and jumpy moments (incidentally that flick was decent for a viewing, but it tried too hard).
It's low budget, it's creepy, it's well pieced together and while the script isn't anything particularly special, the overall package is pleasing - after all, it's ghost/zombie Nazis in a dark, spooky Nazi bunker!
The Good, The Bad, and The Weird:
The last South Korean movie I recall watching was The Host (which also stars one of the same actors) - and I didn't care for it - however this love letter to Sergio Leone (specifically For A Few Dollars More, The Good The Bad and The Ugly, and Once Upon A Time In The West) is a corker. Aside from some second act pacing dips, and a mildy confusing interplay of character groups, it has some brilliant action - a raid on a moving train, a market bullet ballet that ascends to the skies, and an all-out chase after the treasure map featuring multiple factions running and gunning like crazy set to Santa Esmeralda's "Don't Let Me Be Misunderstood" (a possible Tarantino nod?).
In short it is a beautiful-looking, beautifully crafted South Korean take on the Spaghetti Western. Your patience might be tested around the middle portion, but it's entirely worthwhile to stick around and enjoy the spectacle of it all.