Its worth watching once.
Its not some super awesome amazing movie.
It serves its purpose however and there are some really terrifying moments.
This movie will be good or bad based on factors that have everything to do with the viewer.
U have to watch this movie as if it were real, Not some hollywood made movie.
The reason u don't see the monster as much is cause its suppose to be filmed by a guy running from it, so of course he isn't gonna get perfect angles and long shots, cause HELLO, the guy is gonna die if he stops.
If u watch it from the perspective as its meant to be like a documentary. the 9/11 guy who filmed the planes going into the towers, U will love it as the movie seems very very real.
If u are expecting a nice Hollywood crafted movie, u will be disappointed and hate it.
So suspend disbelief. Pretend what u are seeing is actually happening and some guy just so happened to have a camcorder on and u will love it!