I don't really watch horror, much less Korean horror but I did watch
Hansel & Gretel a while back. It wasn't scary and I didn't like how the story unfolded but I give the movie points for how the kids were creepy as fukk. Felt like a 6/10 flick.
Thirst is a vampire horror, it's a fantastic film with a unique take on vampires but I didn't get scared, it has no jump scares or feeling of dread but there's a lot of nasty/queasy shyt that happens to make you feel uncomfortable lol. LOTS of blood
Another movie to look out for if it ever hits netflix is a historical film
Masquerade, Lee Byung-Hun stars in it (main lead from A Bittersweet Life, I Saw The Devil).