Now, in the past I've found Korean films to be hit or miss. Either they're kind of awful or really good. Luckily this one turned out to be one of the really good ones. As a historical war movie you've got tons of scenes of serious-looking dudes in cool-looking armor all over the place.
The ships were very cool and actually looked like something you might want to fight in, as opposed to some of the silly designs you see in fantasy films.
And the battle scenes were great, particularly the desperate boarding melees.