I can understand why many people would like this film. To a certain kind of person this may be very appealing.
But I have to agree with LostMyHairbrush. I am a fan of Korean drama / fantasy / scifi. While this film has a moderately interesting plot and a good twist, it fails to deliver in both directing and acting. The characters come across 2-dimensional and flat, making it difficult for the audience to connect with any of them. The lead female romantic role is meek and uninspiring, the male lead romantic role isn't all that charismatic, making one wonder what she sees in him to begin with. Everything presented it just somewhat bland... which causes the movie to just coast along.
While most such movies present an emotional roller coaster and often have the viewers laughing and weeping multiple times throughout, I never felt really moved by any of this. I'm withholding specific instances to avoid spoilers... but this is somewhat like a nourishing meal, but without significant flavor. There's never really a climax to this film anywhere, at all. It basically starts out telling a story, continues to tell the story, and ends up telling the story without really accomplishing anything more. I didn't really feel much emotion in any of it.
For those who loved the film, I'm glad they did. This will appeal to some viewers. But although I usually very much like this genre, Ditto left me unimpressed. It's been done before, and better. At the end I found myself wondering, "Why the name Ditto? What does that mean in the context of the movie?" And that summed it up there: what was the writer / director trying to get across? It didn't feel real, didn't bring the story home, didn't tug the heart strings. It wound up a 2-hour-long bland meal without dessert.
