The subtitles were fine, and I enjoyed the movie, too, though it just
reminded me of a typical day at an American high school.
I didn't find it as surreal as Andy did. From here, we get a bit
spoilery, so....
SPOILERS!
The American appeared to be in a dream/flashback to the teacher's time
in the US. It was earlier revealed that he had gone to Harvard
University, and later worked at a large, European bank in the US, and,
based it this scene, he appears to have teamed up with another
psychopath, who he ended up killing, during this period in his life. The
scenes with the eyeball in the shotgun were of the other psycho's eye,
and he was talking to his erstwhile partner. No so much surreal as just
the hallucinations of a psychopath. The rest of the film was played as a
pretty straight psycho mass murder.
The choice of music made perfect sense, too, as the lyrics told of a
murderer. It was driving me crazy for a bit, as I recognized the melody
but couldn't place it with the German lyrics (which are eventually
translated into Japanese subs (and thus the English subs, as well). But
we eventually learn that the song was done in English, jazz style, as
"Mack the Knife." Appropriate enough as the theme song for a serial killer.
I did chuckle a bit at the final title on the screen (in English), which
I won't spoil here.
--
Kishin