Finally I thought of a rating for this movie. 7/10.

This movie is really hard to rate, in my opinion. Although I found the acting absolutely brilliant, I wasn't happy with the flow of the movie at all. Also the story is just sick sick sick!!!
I can understand the male lead's actions at first cause he wasn't aware...but the ending??!! Gosh that was gross and messed up!! and SICK!!! *goes to a corner and pukes*

This movie was similar in a way to the movie "No Mercy". The whole revenge idea in "Old Boy" was good but I enjoyed the revenge in 'No Mercy' way way better...that movie was just brilliant and haunting...especially the ending!

So what I 100% enjoyed in "Old Boy" was the acting. The whole cast was brilliant, especially Choi Min Shik. I don't think they could have chosen anyone better for that role!