I just got back from seeing Cloverfield. All I can say is "wow" this is one of the best horror/monster films I have seen in along time. It is certainly worth seeing. Much better than the new Will Smith movie "I am Legend", which ironically also takes place in Manhattan.
The movie is set in Manhattan and covers a period of approximately 10-12 hours. The movie follows five characters as they try to both escape the city and rescue a friend from a monster attacking the city -- all of which the audiences experiences via one of the character's camcorder (think Blair Witch). This is a very different approach to the genre, as one would expect to be getting information and watching the happenings of events from the government or military point of view. Cloverfield basically ignores that perspective and solely focuses on the view and experience of the five friends running through the streets, buildings, and subways of the city.
Though the movie is relatively short, the film is fast paced, packed with action, and very intense -- so it feels like you are in the theater longer than what you really are. The writers and actors do a great job in drawing the audience into the action and letting them experience, even if just a bit, some of the stress and anxiety that they experience when fleeing from a giant monster rampaging through the streets of Manhattan -- without a doubt the shaky camcorder cinematography lends much to the feeling that you are watching a home movie.
The monster is certainly original, I think. It reminds one of Godzilla, or maybe King Kong, or then again it could be something else. That is, you don't really learn much about the monster in the movie. There are enough camera shots of the monster that give you an idea of what it might be, and what is given makes it difficult to form an exhaustive sketch. You will leave the theater trying to figure out what the monster is -- did it come from the ocean, outter space, a worm hole, a botched experiment, biological warfare gone wrong? Who knows. But this is for certain, the monster will be remember when you leave.
If you like happy endings, well there is hope.