It's been a while since I watched this one. It's PG-13 here in the States, as are most of the direct-to-video superhero cartoons. I don't particularly remember the violence; in fact the only part I remember distinctly is the scene with Lois and Martha. I really liked that Lois sought her out like that so they could share in their grief. It surprised me, though, that Clark had never mentioned to his mother that he had a girlfriend. Various incarnations of Clark have confided in his parents to varying degrees, if they're even around, but I'd think that if he was in contact with his mother at all he would mention to her that he was in a serious relationship.
As far as the source material goes, the Death of Superman is mostly a super-brawl, with most of the Justice League ending up in intensive care. It's an interesting read, as far as it goes, but I think the real gems are the Funeral for a Friend/World Without a Superman and Reign of the Supermen stories that followed it. The first story (which has had two different titles) shows the world's and Superman's friends' reactions to his death, and the second story shows his return. They're well worth the read.
