I struggled to get through this film and finally gave up about 70 minutes in.
This entire film is apparently a showcase for the (American) lead actor's Japanese speaking ability. As a story, it is predictable and laughable and not really that interesting.
There is a lot of unnecessary dialogue, there are over-the-top screaming scenes (which are de rigueur for Japanese films, even, apparently, ones featuring foreign leads), there are tired tropes (English teachers in Japan), and there are huge miscalculations by the writer/star, mainly about why anyone would care that he can speak Japanese as well as he does.
The entire onsen scene came across as totally unbelievable and bizarre and fake.
The lead actor does tons of mugging and has apparently learned every single Japanese facial expression or reaction, since he has very few of his own.
His character is not developed at all, and as such, I could not care what happens to him.
The Japanese actors all fare better, and the lead Japanese "half" actor is legitimately hot and sexy and has potential in the right story (not this one).
There was tons of unnecessary (and incorrectly chosen) music with singing, played over scenes where the actors were talking -- and yet, how could we understand what they were saying when they were being drowned out by background music?
The two star rating is for the hot Japanese male lead, who gives us a hint of what paradise might be like in the onsen, but it is nearly totally destroyed by the virginal worry-wart first-time-ever in an onsen foreigner who acts like a scared girl on her first date.
I have lived in Japan for a long time and I understand a lot of what was going on, and the idea that we are supposed to care about anyone in this film is one that apparently never occurred to the writer/star, since he spent his entire time on screen being obvious about everything he said and did, all without a soupçon of subtlety.
