I wasn't satisfied with the ending though. It didn't feel right. You see, at first it seemed that our main guy Han Tae Joo had time travelled from the present 2018 to the past 1988. Later, the story seemed to establish that he did not actually time travel. Instead all that was happening was a vivid dream as he was in a one-month-coma. He then woke up from his coma, back to the present 2018 where life supposedly and logically really was. However, he couldn't ignore the 1988 cry for help just before he woke up so he was shown later to jump off a building and bam, he was back in 1988. He decided to stay. The end. So what, did he jump to his death? Did he die? Just to return to a world that once seemed vividly real but at the same time may not be possible, given that the possibility of time travel wasn't properly establish? Also, leaving his mother, his real and alive mother, in the real world?! For 1988? Don't leave your mother man, don't leave your mother.
Overall, a nice drama. I would say go for it.