Back to 1989 (2016)

Both dramas have the same premise. The protagonists never met their fathers and have strained relationship with their mothers. Mysterious force sent them back to a time before their birth when they would meet their younger moms and become friends with them.

I recommend this both drama because , Male lead and Female lead
try to solve problem
In one drama explosion and another student murder/suicide

Time Travel is how these two are similar; albeit, Hit the Top has more of a comedic focus. The characters are very relatable in both of these dramas and seem to be very fleshed out. The resolutions in these programs leave you satisfied in my opinion. Both of these are top-notch.

They both have a similar story. In both the male lead has an argument with their parent and gets sent back in time to the year before they were born to get to know their parent and understand why their parent made certain choices. In both the male lead finds love along the way.

Both taiwanese drama about time travel to the past about 20 years. Both very touching and focused on relationship between 2 people from different timelines.

In both shows we can see fatherless main leads, who travel back in time in order to learn about past. Both shows contain romance, but Time traveller 's ending is more bittersweet(or just sad).

They have the same atmosphere(80s/90s vibe), and feel somewhat similar, the biggest difference is that in reply 1994 the isn't any time travel.

Both have male leads which mistakenly go back in time to a certain point, even though in manhole the male lead went back to his school days and in back to 1989 he goes back to the year before he was born

back to 1989 is pretty good series with time travel theme.The ML is really smart and a good businessman but he has problem where he wants to find out who his father is,then one night he accidentally goes back in time when his mother was still young and close to the time where she got pregnant with him.......

ML accidentally time travels and meets his parents' younger selves...
He brings modern technology with him too
Similar story where ML learns of the hardships of his parents

Both take place in the late 1980s and both explore the romance between people who start off as friends. Back to 1989 includes time travel though and is a Taiwanese drama, not a Korean one.

Mistaken timetravel, love you didn't know existed and changing the past.

Similar Supernatural Story. A chance to change for the better for the selfish protagonist.
A bit more character driven to be honest

Both plots take place in a similar time period involving college/graduate students dealing with first love problems.

Both plots have a superficial lightheartedness with moments of darkness and underlying regret.

See You In Time is another Taiwanese drama dealing with time plots. This one involves the future and the character's efforts to change it. Also it stars Mini Tsai who plays in Back to 1989!