I wanted to restrain myself from having some high expectations about this movie but I couldn't. The book was one of my favorites as a child.
Comparing the original story line, the movie did not change that much the course of events. However, they applied the classic old horror movie recipe - jump-scares and dramatic music (in scenes when it was clearly not the case) - and transformed the whole product into some cheap stuff.
The way the movie was filmed and put together as an artistic product makes me think of the Discovery TV shows that were showing reconstitutions of murders and strange events --> cheap and almost schematic.
It's a pity, the story remains one of great value, but anything else, not so much.
PS : The cat was, indeed, truly beautiful and good chosen.
Review of Pet Sematary
