As someone who sees a lot of horror films, and so gives many of them leeway, let me say that this is a movie that I think just about anyone would be satisfied with as a creepy, disturbing, emotional night at the movies.
The plot is pretty basic - gene scientists use human DNA when told not to and make something that is kind of human, and then raise it. The movie does a good job of being a mad-science/monster movie with a pulpy plot, without being stupid, which is pretty hard to pull off nowadays (yeah, they cut a few corners plot/logic wise, but I did say pulpy, didn't I?). SPLICE is basically "Child of David Cronenberg's THE FLY/THE BROOD and Larry Cohen's IT'S ALIVE" - not as deep as Cronenberg's films, but with some very powerful emotional resonance. The actress playing DREN, the life form, is very, very good. Nice to see another horror film about adult characters (although the "rock star geneticist" characterization is a bit hard for me to swallow) that has nice pacing (you never feel like "oh, here's the disposable character who'll get killed at the halfway point to prove it's a horror movie by upping the body count"), with everything mostly simmering until the mayhem of the ending.
Seriously, worth seeing - it doesn't insult your intelligence and, while I wouldn't say it's "scary", it is creepy and, at times, profoundly disturbing.<