Factual error: When 47 shoots the two soldiers in the hotel, they die instantly. In reality, a person shot with only one bullet still has about 1-2 minutes of normal body functions before they lose consciousness - it is not unknown for people to fail to realise that they have been shot. (Police trainers often report that their students are surprised when their targets aren't killed at once but instead get back up and retaliate). The soldiers wouldn't have been taken out instantly and should have had more than enough time to fight back. And they were wearing body armour, which should have been enough to stop a pistol bullet from causing an instant kill.
Factual error: At the scene in the church, there are lots of security personnel standing around wearing steel helmets. The helmet type seems to be an East German M56 helmet (standard for the East German Armed forces until reunification). There is no reason why a Russian security force would have the M56 helmet. (Only if the makers of the movie where able to purchase a lot cheaply :).)