I watched the first one, not knowing exactly what it was, out of boredom and didn't expect too much.
I'm glad I did. Its like a cool peppermint patty on a hot summer day.
It's about a sorority house that's plagued with a serial killer. Your typical teen slasher movie, but with a twist. This is funny as all get-out and the gore and violence is done with, well, taste.
It's not a "Scary Movie" kind of funny, but it's very well scripted and acted. I find it hard to believe the actors and actresses can say their lines with their tongues so firmly in their cheeks. You have to know that a gag reel would be priceless.
So, I'd say that if Scary Movie, Van Wilder, Animal House, and Heathers had a child, this would be it.
Don't analyze it. Just get a bow of popcorn and prepare to be entertained.