In both female leads in 1st part of movie is cute and relies on the male lead.
Difference is in LBF&D the FL becomes the god and plays amnesia to the ML whereas in Song of the moon its the male lead.

Style: tense, disturbing, captivating, realistic, suspenseful.

Plot: maniac, serial killer, whodunit, psychological manipulation, investigation, sociopath, cruelty, psychopath, justice, crime solving, police, crimes, murderer
kidnapping, evil, torture.

same vibes with same tyoe of suspense, thriller, murder and 3 main leads , story simlar linked with the past of the main leads,

if you like the voice Korean drama , you will enjoy this one also, same suspense, same type of thriller linked with a past.

Its the plot story of this series in film version. Was also made this year
The answer to the question of who and why Hu Yidao was killed is straight forward there .

similar type of male lead in both
male lead also egocentric in both
warm female lead in both
Female lead always trying to please others in both
Female makes a choice at a crucial moment in her life in both .
supportive actors have similar role
cohabitation- marriage
though the marriage in FTLU is arranged whereas its by choice n love.
Both are nice series, If you enjoyed one you will enjoy the other.

Both have a nice team work among the heroes
Both have a common member as vilain
Both have a very supportive and brave female lead
If you enjoyed the quest mission in The Eight ,you will like Maiden Holmes

Both have quests to complete
Both female lead are always backing up the main male
Lead
Both had a team to to work with them
Both have good martial arts action
Both have a close personality as vilain
The only difference is The Eight has a happy ending compared to Martial Universe