I'm not a big drama fan but this one drew me in, I like the sci-fi element to it, and the humor is quite good, and some of the acting is excellent. It is fun to see their take on the alternative history.
he show isn't quite perfect for me though, there is a lot of unnecessary jumping slightly back and forward in time, so you end up seeing the same events repeatedly, which feels a bit like padding the runtime. And I know it's a drama trope, but the long, long, long slow motion lovey-dovey moments feel really out of place in what is otherwise a story that moves along quite quickly.
The time skipping and repeated events tend to make the story more confusing than it needs to be. The story is fairly straightforward, and well executed for the most part, but seeing something happen, then going back in time a little bit just to see it happen again, makes parts of it feel more complicated than they are, for no reason.
The music is pretty good for the most part too, although a few of the slower songs are terrible, and some of the love theme songs, especially the ones that starts with the acoustic guitar, are played too often and get eye-rolling to hear so often.
Still, I do like the show, and I am really interested to see how it plays out. I have some theories as to what will happen, and 우도환 is really excellent in his roles, especially as he has to start mixing the two characters. I almost feel like it's a shame the show was designed as a drama, because I think if the show had been allowed to break the mold a little bit, and be a little bit more adventure and slightly less "dramatic", it could have been significantly better. As it is, it feels like an excellent show that got crammed into a suit that didn't quite fit.