Just watched this for a second time to try to understand what I missed when I didn't like this first time around. I missed nothing. This is not a good film.
The first half of the film is great. The last half is just not good. Great cast. Great premise. However, it feels like they ran out of ideas, gave up, and ended up using exposition to wrap the film up quickly.
Very disappointing. Shaun of the Dead was fantastic, and Hot Fuzz doubly so; don't waste your time with this.