Seriously, read the book, or listen to the audiobook, you will have a much better time.
This movie is filmed like a bad video clip, to save on SFX we will shake the camera a LOT so that viewers wont see very well, put in EVERY CLICHÉS of horror movies in there (flashing light in dark corridor, ridiculously precise head-shoot from a 10 year old holding a 9mm one handed, then you have highly trained Marines/soldiers missing a point-blank shot ...culminating in a "VERY FAR FETCHED" and "thinly-stretched suspension of disbelief" ending... which has ABSOLUTELY NOTHING to do with the book.)
It _may_ be an interesting rental on a rainy day, but I'd recommend these movies way before -if you have not seen them:
1 -"REC" whether in the original Spanish or the US remake (which is almost a frame-by-frame remake) Great entertainment! MUST-SEE!
2 + 3 "Zombieland" / "Shawn of the Dead" (both EXCELLENT zombie parodies for a great double feature on a rainy Saturday)
4 -The original 1968 "Night of the Living Dead" (the great B&W classic!) cheesy SFX but the claustrophobia of the farmhouse still is excellent
5 -or its 1990 remake "Night of the Living Dead" (Savini) is more Gore than you need, and the ending is completely different! :D
6 - "The Dead" Starring Rob Freeman and Prince David Oseia (2010)(a South African Daytime Zombie movie -many cliché- but a fun twist on the genre with good acting)