I know that feel.
Deranged - disaster movie about an outbreak of a parasite that makes people drown themselves
Most of Kim Jee-woon's movies are top kino - a lot of well made action movies
All of Na Hong-jin's feature movies - two excellent crime/action crime movies and one decent horror
The City of Violence - similar to a lot of Korean crime films but with was more hand-to-hand combat
This was a bit of a random selection but I have a long list of Korean movies on an old laptop with some more obscure stuff on it, reply if you're interested in seeing some of em