The biggest problem with Japanese films and dramas is the acting and the camerawork. Confidence Man is no exception. The main character in particular at times feels like she is an anime character instead of a real human being. She is an unbelievable character. The other characters are surprisingly well written.
The lighting in this film is awful. For some reason the backgrounds are all super bright and over exposed. I don't know who chose this, but it was a poor decision.
I will praise the film for being light hearted and having an enjoyable story, there are several plot holes. The biggest being the money that the characters earn through their scams. In the real world, you cannot just use this money as it would raise suspicion. The main characters are all jobless yet they have millions upon millions of dollars. This would arouse suspicion and they would be arrested rather quickly, especially considering they keep their money in bank accounts instead of in cash in secret hiding places.
If these plot holes are ignored, it is possible to have a good time with Confidence Man JP. If you enjoyed it, I would recommend the anime series Great Pretender which is basically the exact same thing with a much more serious tone.