Factual error: The idea that anyone survived living long term in Pripyat Hospital is absurd. At the time the film was set the hospital was still radioactive and prolonged exposure by living there would be fatal. Nobody could survive on the grounds for more than two or three months without receiving a lethal dose of radioactivity. Incidentally, prolonged exposure to radioactivity doesn't turn you into a deranged zombie - it turns you into a corpse.
Factual error: The whole basis of the movie is flawed. You could not pick a more inappropriate location for a babes-in-the-wood style zombie film. The Exclusion Zone around the Chernobyl reactor site is not a deserted wasteland as shown in this film - it is one of the most secure and well patrolled areas on earth. It is crawling with police, military and paramilitary patrols and if you did manage to get lost all you'd have to do is walk or drive five minutes in any direction and you'd run into someone who could help. If there really was a population of mutated zombies about the place they would have been located and dealt with years ago. You cannot just drive into Pripyat (the setting of this film). To get there you would have to pass through two checkpoints, and a private vehicle would be refused entry. Further, the Exclusion Zone is (believe it or not) a popular tourist spot and the single road through is an important transit route for heavy goods vehicles driving to and from Kiev. In other words, you are never far from someone who could help, probably by shooting the zombie with his AK47. And as for mobile telephone masts - the place is festooned with them and you can make a call any time of the night and day.
Plot hole: Natalie uses her cell phone to record the injured and bleeding Chris, but it never occurs to her to use the phone to call for help? And how is it possible that in 2012, she seems to be the only one with a cell phone? It is simply not possible that she could not get a signal - the Chernobyl Exclusion Zone is festooned with mobile telephone masts - precisely because of the inherent danger of being lost there.
Suggested correction: Uri said at the beginning of the film that he has never gotten a signal whilst in that area.
Then Uri is wrong, or he is lying for some bizarre reason. The Chernobyl Exclusion Zone is festooned with mobile antenna masts and if there was one place on earth where you could absolutely guarantee getting a signal, it is there.
Other mistake: At the end, we learn that the predators are escaped patients from a hospital, ostensibly horribly mutated survivors of the accident. But if they've "escaped" into Pripyat, the hospital must be located inside the exclusion zone, and why in the world would they use a hospital there? All patients and staff were evacuated from the Pripyat hospital on April 29th 1986.
Suggested correction: The exclusion zone is only 30km. A hospital could have been built or other structure repurposed outside of the EZ. Simply walking at a normal pace, one can easily traverse 30km in a single day. Also, it's not an actual hospital that treats sick people. It's a clandestine operation to perform experiments on these mutated individuals.
Suggested correction: While most of your points are factual, the mutants haven't been living in the exclusion zone for years. They are recently escaped patients from the hospital shown at the end of the film. When the guards tell Yuri that the zone is closed for maintenance, that's just a cover for the government to go in and recapture the mutants. That's why he makes it a point to say that it's unusual that the guards didn't tell him ahead of time that they would be closed for maintenance because they usually do.