An old actor returns years later to the role that made him famous--that of evil, psychopathic killer, Dr. Death. But why does everyone on the movie set keep dying violently? Alright, so it's not either one's greatest film, but it is Vincent Price and Peter Cushing, so cut them some slack. The plot is chock-full of holes, but still mildly entertaining, and has a good (if inexplicable) twist ending. That, as well as the two stars, are the only reasons this gets a rating of 6/10 from me.
Would I recommend? Not particularly, as there are much better films you could watch to see Price and Cushing at their best. But it's one of your few chances to see both great actors together, and it isn't a total waste of time.