Recommendations

Both the couple relationships are strong without all the misunderstanding/breakups. Hard to find a enjoyable no cringe worthy drama to watch like these

Because Lee Joon Gi and Moon Chae Won previously starred together in Criminal Minds. And their chemistry is no joke JJANG!

Both raw indie like romance movies, only that in Theater a Love Story" is the male lead that tries to chase his dreams

This is literally the same historical event but retold from another character's POV. The villains become heroes and vice versa. While I love Zhou Xun as Ulanara/Ruyi in RRLP more, she's about the only character who's developed better.
Everyone else (Concubine Ling, Emperor Qianlong, Empress Rongyin, etc) is developed and acted much better. Special mention to Wu Jin Yan as Concubine Ling (here called Wei Ying Luo, because history never recorded her real name) and Nie Yuan as Emperor Qianlong.

both japanese short movies follow high school students who are bored of the small town they live in and their uneventful life. There is a focus on friendship and youth. And so we put goldfish in the pool is way more 'loud' and out there with its editing etc while She's Gone is more quiet (and kinda confusing tbh..)

Well, hyena is about lawyer but it has some similar points. Both drama have the plot that 2 main leads hate each other but then they have to work together to solve crimes. Hyena also have a little bit of romance

Exact same premise but you are just watching how they manage their daily lives in an isolate location. All the activities will be created by themselves. It is set in a forest like area.

Both include book and the characters inside said book. Both include human falling in love with fiction character.

Both have FL fall in love with fictional ML. My Dear Warrior has more supporting cast involvement than in W.

It’s basically a remake except the night of the comet 2 has a happy ending and the plot is different. The only thing similar is the alternate universe concept!

Neglected rich boy has been cared for by his loyal poor bff/protector for ~years, yet when it comes to telling the whole truth about their *real* feelings, they have quite a difficult time getting there. In LA, the rich one returns from an extensive overseas stay & discovers their bff now seems to have eyes for someone else.. & a messy "mostly straight" triangle ensues (& is yet to be resolved years later). In WYEL, things are handled somewhat better, & with a much ~brighter ending, at least. <3

Must-see fanvid rec:
https://youtu.be/sOWPbqQsEu0

Also, a total tease:
https://youtu.be/ynQZp7P8EQc

Both are socially aware films that focus on discrimination and oppression of those who are weak in society (those who are poor or those who are immigrants or unattractive).

Similar premise: Alien beings treated as gods. Romance between one of those said gods and a female warrior. Battle of the gods affecting the human realm.

both chinese movies from the 90s have a chinese opera element (Farewell my Concubine revolves heavily around Chinese opera and in Raise the Red Lantern one of the characters was an opera singer) and that connection to opera also shows in the osts. The stories start in the 1920s where our main protagonists get send off by their mothers, have a kind of betrayal element and dont end happily. Also Dong Li stars in both films.

Teiichi is comparable to Kaguya as both are elites who are proud, competitive and strategic in their plans. The difference lies in their motive. While Teiichi is vying for the position of becoming president, Kaguya, is ploying to make the President confess to her. They are also unintentionally funny, and that's one of the reasons why I like these two movies so much.

Note: If you haven't seen the anime of Kaguya-sama: Love is War, it is definitely better since it is longer (it already has 2 seasons). But of course, I still appreciate the live action.