In the beginning of the first part of the series, the officers in the police station are talking and walking out of the room, the sound effect of stepping and opening the door was the sounds used in the original PSX version of Resident Evil.
All of the beatings in the film were real. They were people who owed Vitaly and his gang money in real life, the beatings in the film were a form of payment so rather give Vitaly extortion money, they provided stunts for his film. All blood in film was real.