There are many parallels between these two stories. The main similarities are (while trying to avoid major spoilers):
- A gay relationship started in school.
- At some point, one of the characters bows to societal expectations and ends the relationship.
- That character gets married to a woman and struggles to live the lie, resulting in an emotionally messy fall-out for everyone.
- There is a satisfying resolution/ending (*must watch Life Love On The Line Director's Cut which extends the ending by 7 minutes; the original version does not feel satisfying at the end!)
- They are both realistic in their approach to characters and there are moments of heavy feels.

The main differences:
- A main component to His is the 6 year old daughter of one of the gay men.
- The lighting (and cinematography) in Life is symbolic, really sets moods, is often beautiful, and is memorable.
- I felt that His was a slightly 'lighter' watch throughout than Life; one reason being that the daughter frequently brought a lot of heart-warming brightness.

Both have a student and a mafia member falling for each other. (In My Dear Gangster it is a university student and in Kiseki it is a highschool student.)
The mafia members want to leave their groups and live a regular life with their love interests.

While there is some drama in both, My Dear Gangster Oppa is lighter in tone than Kiseki Dear To Me.

Kiseki was consistantly great while My Dear Gangster was fun through Ep 5 (out of 8), then it fell apart. My recommendation for My Dear Gangster is to watch Ep 1-4 then treat Ep 5 as a fluffy epilogue and stop at 38min.