Japanese short episodic mystery dramas about a girl and a man investigating locked room murders and other cases.

A less-than-human-becoming-human journey.

One of main characters in both movie and drama is a very similar dark (scary, but also kinda... cute?) psycho with some deep issues and history of psychological (mis)treatment. Both stories show us a lot of violence and you can't really figure out the psycho character till the very end.

Difference between these two is mostly that Bad Guys is a drama and not a movie (so not as short and has more story parts intertwined) and has other significant and complicated characters aside from the psycho.

Very similar. Teenage vampire love. Young vampire's coming of age, love with a human, some unfrendlies that get in the way...

Both shows have a lot of suspense and action. The story is about a teenage boy that is involved (because of blood ties (in HTE) or by being a talented hacker (in BM)) in a struggle of law enforcement against terrorists. In both shows the protagonists gradually, step by step, find out the real intentions of the criminals and (may be) "save the world" in the end.

Both shows are about a detective who sees ghosts of the victims. The ghosts help in the investigations. In both shows the mood is a bit on a dark side.
The main difference pretty much is that BORDER is a Japanese show while Ghost-Seeing Detective Cheo Yong is a Korean one... with all the usual consequences. Also, the ending [which I am not going to spoil here] is not really similar. Otherwise, pretty decent ghost detective stories, both of them.

All the surrounding and circumstances are different, but the feelings between the main couples (the "type" of love) in these two dramas seem similar to me. They start out with almost enemy like relationship, the man treats the woman sometimes really badly... but the girl in both dramas is the type who can take it all and some more, very strong girls both of them. Both pairs also end up in a difficult situation later on where they need to decide how much they can give up for their love.

Both psychological dramas, both deal with manipulating other people into looking into themselves and may be changing for the better. Both have a cute and crazy lead character with a past. :)