Oldboy
Really fantastic film, there's a reason behind the hype it receives.
If you can watch this movie without knowing the twist beforehand, it really improves the value of the movie. I wasn't aware of what the twist was exactly, but I have always heard of how disgusting a twist it is. Without having heard that, I don't think I would have pieced together the twist as early as I did, but even then, it still took some time.
Not really anything bad to say about the film. Fight scenes were awesome, the story was built up perfectly, the acting was great, and everything else was overall incredible.
Maybe not a film I would revisit very often, I don't think the same magic could be captured compared to a first-time watch. Definitely a movie worth checking out!