Somehow 18 (2017)

The main lead gets a second chance to do things he regreted doing in the past.But this one he actually time travels back in time.

-Erased is also an anime that I highly recommend, since it would probably be less rushed than the movie. In Japanese, it is 'Boku Dake Ga Inai Machi'-

-both include male roles who are not the most popular in school
-both include time travel
-both are to save the death of a girl they like
-both have the sam vibes but erased is a bit more in the mystery category.

Jung Yeol and Na Ra fell in love with each other and got married. During their marriage, they have grown to hate each other due to their personality differences. They decide to get a divorce. A month later, their divorce will be finalized. But, on the day that they applied for a divorce, they get into a car accident. When they wake up at the hospital, they have both lost their memories and do not remember each other.

Both dramas have same feel.
Both dramas are about MC trying to save his first love from death
Both involve time travelling

Both are time travel drama. In both, the FL dies all the times and ML travels back to the past to save her.

Both are mini dramas with one of the leads traveling to the past to save someone. Both have a school setting in the past parts.

Miyu and Shuya are high school students. They have dated for 2 years. Miyu and Shuya have a promise that no matter what, they will watch a movie together on the first day of each new month. When Miyu and Shuya are on their way to the movie theater, Shuya suddenly cancels their date. Shuya seems like he is hiding something and he acts nervous. Later, Miyu goes to the place where she is supposed to meet Shuya, but she witnesses Shuya getting into a car accident. She panics, but when she wakes up she finds herself on the morning of the accident. Miyu keeps waking up on the day when Shuya got into an accident.

Both are mini dramas and involve time travel and are set partially in school, partially in adulthood.

The characters are preventing something from happening to their loved ones ----------------------------------

The characters are preventing something from happening to their loved ones
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Both are short length dramas where the ML goes back to the past to save the FL from a car accident, sacrificing himself in the process. Both have a final twist and somewhat open ending.

The male lead (28 years old) goes back to his younger body (18 years old) out of nowhere to find why the girl he liked commited suicide.
SIMILARITIES: Age, Younger Body

-Dealing with suicide
-Trying to stop the suicide from happening
-Youth
-Redemption
-Gets better and healed after ordeal
-Never forgets but want to move on

Both are short dramas involving time travelers trying to save a life/lives. Both have unexpected twists.

Both are short (film vs. movie length) dramas featuring time travel, and changing past events for the future. Both have open, but satisfying endings.