I'm not really good as writing reviews but i hope this can be of help to anyone.
I was finally able to find this drama and just finished watching it. This has to be one of THE Best k-drama shows so far. It has an amazing story with great character development, unlike some other dramas, the characters actually felt like they could be real people which i think really adds to the watchability of the series. I really enjoyed the whole 80s vibe as it felt really refreshing compared to dramas based in the 2000s and the romance was just the right amount so that it didn't take over the story. Although some may say the ending is lacking or not that good i think the exact opposite as the ending fits really well with the drama because it doesn't need to be explained in detail or that would (in my opinion) ruin the whole point of ending the series in that way. The whole time travel thing my not be everyones cup of tea but i'd definitely suggest giving it a go you never know you may end up enjoying it.