“Interlude” (2004) IMDb
A typical—in fact nameless—guy is having a fairly standard romance anime high-school life, but gets visions of horrible scenes: His beloved friend since childhood is lifeless in his arms, surrounded by ruins, and people in environmental suits menacingly inspect the aftermath of some unknown disaster. The boy ignores these visions, but is gradually drawn into an undeniable shadow world.
Kitch romantic horror. Starts out like a reasonably competent (if unusually light and romantic) Silent Hill- or Kult-type story with an SF slant, but screws it up with big-titted morons and many other mismatched stereotypes and oddities including an end credits song about the great life in elementary school. The final explanation does almost make sense in a very fuzzy, “poetic” way, but good it is not.