Wow - what a great movie! I've always been a big fan of horror movies, and The Ruins is one of the best I've seen in quite some time. While once again it does include a bunch of sexy young Americans, this batch isn't quite as "dumb" as your typical American teens. I can't speak on behalf of the book, which I haven't read, but the movie did leave a lasting (if horrorifying) impression.
I was especially impressed by Jonathan Tucker, a very sex young actor who shined as a young med school student who had to use some of his training in some of the most gruesome scenes I have seen as of late.
