If you go into it expecting a typical horror movie- you will be disappointed. It isnt a typical horror movie, nor is it meant to be. You know only what the dog knows and a lot of the suspense comes from knowing the dog cannot verbally communicate with his owner as to what hes expiercing. Ive seen people theorize that there weren't actually ghosts, but that Indy was simply trying to fend of death itself, as his owner is very clearly chronically ill.
Ive seen people complain that you're never told what the haunting is or why it's happening, the fact is those things don't matter. You know what the dog knows.
A great movie. Theres a great after credit scene that shows how it was filmed. Indy and his owners were the only ones involved in filming, no film crew. Artistic and emotional and deserving of all the love and praise it's receiving.