Other people are correct in saying that this is similar to John Wick.

I loved this movie!! It was so cool how she had no mercy; she was just so cool. A really good movie, with a good plot and nice cinematography. The bloody fight and chase scenes were so cool! All the flashback scenes of Ok Ju and Min Hee were so sweet and cute to watch, furthermore rooting for the main character to get revenge. I do wish we saw more of their lives (Ok Ju and the high school student) after everything happened. Other than that, I really enjoyed this movie and definitely recommend!