Fun movie, but...
...it seems to me like this films would've had more potential if they'd stuck with the standard "masked killer on the loose." It seemed like the point of the film was to include and/or lampshade as many horror movie tropes as possible. So, if they'd had a masked psycho, there would've been a lot more options than a random monster.
Of course, this is just my opinion. I liked the movie itself; it was fun and entertaining. But it seems like it could have been better if they'd gone in a different direction.
Let a little insanity into your life.