Both are a supernatural/fantasy thriller centered in school, and shows a lot of bad things people can do to be accepted in school and in life. In Girl From Nowhere the FL is the "ghost" and, in Detention, the FL kinda has to deel with the ghost.

Both are about a disasters that affects lots of people, the government doing something reckless and the main lead needing to step up and be the hero.

In both of them they kinda don't have a choice but to play. Being smart and making the right decisions it's what counts.

Liar Game doesn't have gore scenes and deaths but both have "games" that require being smart. They also have this protagonist that wants everyone to win.

Both series have short episodes with differents plots. All episodes are kinda dark and weird. I'm not sure what Til Death Do Us Part is based on, but some seems like urban legends.