Rip off, but such a low rating is unfair!
The overall rating of three point something is incredibly unfair - even if this film is a glaring rip off of "The Exorcist". While it may be immediately comparable to this film, that should also be a way of seeing where it improves on the original. The doll sequence, and in my view the general pace of the film is actually superior to the Exorcist. I also think that the Rosemary's Baby "remix" - having a pregnant mother - is more interesting than the child that is possessed in the Exorcist.
There are some very original moments in this film though. The aforementioned doll sequence, the crazed bananna eating sequence - wonderful manic acting by Mills there, and the brilliant eye sequence - genuinely frightening.
Yes, this has hammy moments and can perhaps never be filmed as a view in it's own right, so from that viewpoint I accept that it will always be regarded as "lesser", but watched as a companion piece to the Exorcist, an unoffical follow up, this rewards on many levels.