Old Boy rip-off? (spoilers)

I noticed several resemblances of 20th Century Boys manga and movie (complete, not only this first part) and South-Korean cult movie Old Boy... Those are:
- The title, 20th Century Boys and Old Boy (in the Old Boy movie they say that the name of school that main character went is Evergreen Old Boys)
- The main character knows that the villain is somebody from his class but he can't remember who it is so he research it...
- It all happens because of some trauma that main villain had in his childhood and in both cases it was sort of misunderstanding.
- In the beginning of Old Boy the main character is drunk and he end up in Police. Similar segment appears in 20th Century Boys when two policemen get drunk and the "evil" policeman kills the good one.
- In Old Boy the villian unleashes poison in the prisoner's room, while in the 20th Century Boy there is also a poison unleashed in the world.
- In Old Boy the villain uses hypnoses for his plot, in 20th Century Boys the villain uses hypnoses to get his cult members.
- And most importantly the main villain is in both cases somebody who is mentally still a child...

So if you exclude SF, anime and rock music elements from the 20th Century Boys you get something very similar to Old Boy...