I was surprised to see that the script was improvised by the cast during filming. This would explain the natural language used throughout the film. Obviously there was a good idea framework it was based around, otherwise it would've been just a mess. Truthfully, there are a few holes in the plot that never were explained, which could be as a result of the improvisation. Like for example, in the opening scene, we see our hero, Joseph, standing in front of his girlfriend, Laura, breaking up; this would not warrant any special attention except for the fact that Joseph was standing there totally naked, and Laura was totally clothed. Were they just having sex and she dumps him right afterwards? Did she just come in just as he was about go for a shower or something? It made no sense there was no need for Joseph to be totally naked, and the rest of the movie has very little to with sex, and more to do with relationships; I can only think the filmmakers put a nude scene in there to get an "R" rating, and get some controversy.
There are some brilliant touches in the movie. Check out the scene in the disco where our four friends go after a dinner out together. The disco is so loud that nobody can hear each other even while shouting at each other. All of the communications is done through exaggerated body language and lip-reading. I found it fun trying to figure out the dialogue of their body language, and make up the dialogue in my own head based on their body language.
Another scene that was great was when Bruce, the supposed one-woman man who dreams about other women, comes clean to his wife, Yumi. The reactions are totally unexpected during their dialogue, and it didn't come out in the way that I would've normally expected when a man and wife are discussing their infidelities. And the dialogue was entirely in Japanese too, so which added another unexpected twist to it.
Check it out.