Sequelitis: Happened with both versions. The sequel to the '77 original is almost universally regarded as being irredeemably awful, and Craven himself admitted he did it for the money. The sequel to the '06 version does have a few fans, but generally isn't too well regarded itself.
Nightmare Fuel: The very concept of the film, especially if you take into account that it was inspired by the story of Sawney Beane .
Ugly Cute: Ruby, the mutant who protects Doug and Catherine from her mutated family.
Venus and Mercury, the two mutant children. The fact that they don't attack Doug and act like normal kids (in contrast to their family) is a bonus.