Derenzo’s review published on Letterboxd:
It may sound (and it certainly seems) cruel to willfully murder animals on screen as Cannibal Holocaust is notorious for and wont to do.
However, this techinque (moralistically dubious as it may be) allows the movie to transcend the mere presence of a gore picture. By the time the cannibals begin killing the filmmakers, you believe it wholeheartedly. You are not thinking "Oh my, what a wonderful special effect that is." You're thinking "Jesus fuck, they're fucking killing these fucking people!"
It is a grand illusion indeed. So grand and complete that it managed to get the film banned all over the place and put Deodato himself in the hot seat. Now that's filmmaking. That is the art of illusion.
Which goes hand and hand with it as a found footage film. I believe it to be the finest (if not perhaps the only good example I've seen) as it achieves what so many have failed to in its wake - make you believe that what you're witnessing is real. And maybe it takes that kind of on-screen cruelty to sell the premise.
Additionally, the score for this film is so haunting, so tonally at odds in some spots and yet so spot-on in others, that it vibrates in the mind long after the credits have rolled.