Travis Lytle’s review published on Letterboxd:
A werewolf mystery that asks its audience to guess who the beast is, Paul Annett's "The Beast Must Die" combines a fun concept with lackluster execution. The Amicus production boasts a sturdy cast but lacks the energy and atmosphere to make it anything more than mildly watchable.
The plot revolves around a wealthy, big game hunter who has taken down nearly every type of animal. Assembling a group of people at his home, he declares his intention of tracking his biggest quarry: a werewolf. The story casts suspicion on all of the hunter's guest, and, literally, asks its audience to solve the mystery of which guest is the titular monster.
It is a compelling story idea with some fun moments, but the whole thing is carried out with little style or urgency. Its swinging, 1970s soundtrack does not help matters, but its cast, Calvin Lockhart, Peter Cushing, Michael Gambon and others, is committed. The mystery could have been propulsive, but it can not drive the production itself to be livelier.
A horror film without much horror, "The Beast Must Die" is mildly engaging but offers little spirit or entertainment. While it is enjoyable seeing a young Michael Gambon perform with a poorly wigged Peter Cushing, the film generates few real thrills and little solid appeal.