Another exorcist priest saw this film and here's what he had to say

https://youtu.be/PwDeGXv-hTU?t=78

He met the priest who this film is based on - they discussed their approaches to exorcism. He's also performed many exorcisms himself - and basically.... he says this film is BS. There are no flying peeps - no twisting of the neck - and actually, no danger to the priest. In fact.... the only people who have died during past exorcisms are the 'possessed' themselves - and that's usually because of how exorcisms were performed - where, for example, the 'possessed' were not fed or given water, to 'weaken the demon' lol

Article about some of the deaths that have occurred - https://theconversation.com/the-catholic-churchs-views-on-exorcism-have-changed-a-religious-studies-scholar-explains-why-182212

Meanwhile, here is a segment from the 1991 exorcism caught on tape - the narrator states that the 'possessed' in question might be on the verge of levitating - which, as the priest in the first video states is utter BS.
https://youtu.be/VAcvbvqqe7s?t=156