The PG rating
I love this film, but I have to say that for some reason I have a bias against horror movies that aren't rated R because, in my mind, they're not for adults. I watched "It's Alive" again today, and while I don't think its violence quite merits an R rating, it seems to come close at times. Maybe if it were rated R it would just have more gore, which this film does fine without.
I can't name that many other really good horror films that were just rated PG, other than perhaps "The Stepford Wives," which wasn't totally a horror film anyway.
Any thoughts?