The movie itself, despite the melodramatic and conspiracy subplots, does leave this impression that Superman did blow his brains out all over his Fortress of Solitude. I have to agree with that assessment as well.

Interestingly, I remember reading a piece once written by Mark Hamill. Yes, Luke Skywalker, but a major comics nerd he still, and as a kid, like many of the 1950s, he loved that SUPERMAN series. He wrote of how Reeves' suicide was like the first "close" person to have died that he cared about. Real riveting stuff.