The biggest criticism I have on this movie is how it was marketed back in the day. It was marketed as a sequel to Cloverfield which everyone was looking forward to. Then the movie released and turned out to have basically nothing to do with Cloverfield. It wasn't a sequel, it just took place in the Cloverfield universe. It could have very easily not have been in the Cloverfield universe and still be a great movie.
The movie itself is very good in my opinion. The tension is built up all the way through and you can actually feel uncomfortable watching it, as it sucks you into the story.
Excellent movie, just don't expect a Cloverfield sequel.