Ok first of all, Some people are saying that Kelly was driving the car that killed Cassie and she wasnt. Remember earlier in the film when Kelly and the guy who she rode in the car with BOTH died in the meat grinder or whatever it is. It was not Kelly driving the car. And Could someone please tell me How/Why Cassie shaved her head? I mean that was just so confusing. One bad thing about this movie was you dont know what Is a dream and what is really happening!
shareSome spoilers ahead...
I just watched this movie last night. I definitely wouldn't recommend it to anyone who likes these "types" of movies. The acting was bad, the characters were bad (Tony being the worst -- melancholy and mumbling the whole time; too bad he didn't die a gruesome death earlier on).
To answer your questions:
It WAS Kelly driving the car that hit Cassie. The stuff that you saw in the middle of the movie with Kelly and the guy who picked her up after the accident were dreamed by Cassie, but did not HAPPEN until AFTER Cassie killed Alice and left the house. As she was walking down the road, her dream about Kelly came true.
The killer, Alice, had a hair fetish, which is why Cassie shaved her head at the end. It bought her some time to get away as it made Alice pause for a bit.