Great idea! I'm in you same situation all the movies I've bought so far are Blind Buys
I know that maybe it wont help you because you already have the title from CJ Ent. But I could post two words regarding the movies I've already seen:
White Night: The way to better appreciate this movie is to watch it as a sort of an "Almodovar Melodrama" in Korean sauce more than a Thriller... anyway it's a rather average movie and imo it does not deserve all the good reviews it received from the press... anyway for being the director's first feature is not so bad.
Spellbound: A cute romantic comedy with ghosts... far from being flawless, I enjoyed it very much.
Bleak Night: the originality of this movie consists in the fact that the problem of teenagers bullying is view more from the side of the offender than of the victims. I really liked it.
Dancing Queen: a comedy that could be interesting for the non-korean audience in order to know how "modern" the country is now, especially regarding some subjet (women's right, for instance)... otherwise it's a light comedy acted and with some song performed by Uhm Jung-hwa, a very popular Pop-Star in her country, surnamed "Madonna of Korea".
Helpless: as White Night, another K-movie based on a Japanese Novel... good as a melodrama, with a better mistery plot on it... I've largely preferred this one.
Radio Star: a history of a male friendship narrated delicately... A rather funny and cute movie, not particulary original in any way.
Deranged: the first Korean Thriller about a killing mass disease... not bad, definitely better than contagion as a genre movie lol.
R2B: A sort of korean answer to Top Gun with 25 year of delay, starring the K-Pop superstar "Rain". I was impressed by the quality of action scenes (and a bit worried about how the North Korean are described... they still hate each other this much?

). But the plot, despite some funny moments, are the most predictable one can conceive.
Hope it will be of any help to someone.