If you're going to write a movie review....

...for something like a newspaper or a website that gets read by a lot of people, even if it's not read by a lot of people.

And what you're reviewing is based on another source (a book, a comic, an older movie), you should NOT mention the source material.

You're not writing a compare and contrast of the source and the adaptation.

You're not reviewing the source material.

You ARE reviewing the adaptation.

Though its okay for you personally to not like something because it isn't like the source material, its not okay to be "Reviewing" the adaptation and say it isn't good/or you were disappointed because its nothing like the source.

Like the Thomas Harris novel Hannibal and the film Hannibal. While the movie is very close to the book, there are still A LOT of differences. But if I was writing a review for it I wouldn't mention the book (except for maybe how it is in fact based on a book), nor (in my personal opinion) it's superiority. I would talk about the movie, what worked, what didn't work, and how much I enjoyed it, because I do.

Or The H.G. Well's novel The War of the Worlds, and the Steven Spielberg movie War of the Worlds. I LOVE The War of the Worlds novel, and despise the Spielberg movie (my hatred for Spielberg aside). If I was going to write a review for the Spielberg movie I wouldn't even have to mention the differences from it and the novel to talk about how much I think its awful/hate/loathe/have disdain for it.