like many have said before me, if you are going into this movie expecting some potential Oscar material you will be sadly disappointed. The best way to approach this movie is to not expect anything at all but a bit of over the top entertainment provided by an out of control high school party. If you are too old to remember the days when you were in high school and attended a party that seemed to get a little bit crazy, I would not watch this movie. I think you need to have had some kind of crazy party experience in the past in order to take that event in your mind and multiply it by 100 times. But you won't HAVE to create that scenario in your head, because that is exactly what project X does for you.
There really is not much of a story. But that being said, there are some theatrical elements that will set up for scenes later in the movie. So in that respect there is a sort of a story line and a decent attempt at unfolding events.
The characters aren't THAT bad. There is some character establishment although they may not be entirely likable. While they do establish the characters, there is not much development. Right from the beginning of the movie you get a good sense of the characters and that is what you can expect the whole movie. I didn't think the secondary characters are too horrible either. The 12 year old security guards, an angry midget and the angry drug dealer all create for some great mind numbing entertainment.
Basically if you are over the age of 35 MAX, depending how young hearted you are. Or if you can't recall a crazy high school or college party experience to relate to, I would not recommend this movie. People are going to talk trash on this movie, because they were expecting something more upon going to see this. DON'T! Some people ask a lot out of movies. They need plot twists and turns surprises and thrills. This movie does contain some of that but in a dumbed down, mind numbing fashion. So don't expect anything other than some wild, over-the-top, epic party experience of the century and you should be OK.