The original UK cinema version was cut by the BBFC and lost part of the final climactic stabbing plus the closeup shot of Pluto's bloodied and mauled ankle. The initial 1987 video release on the Palace label surprisingly restored all of the previous cuts but lost a brief 2 second scene where Mars points a gun at Brenda's open mouth. The 2003 Anchor Bay release saw all BBFC cuts fully restored.
Some Canadian VHS copies are missing most of the credits at the beginning.
Also of note in the Jaguar/World of Video 2000 release is the editing of the sequence with Bob's decapitated head. There are great chunks of the film cut away at points where you see his head, although it is visible for a couple of seconds. This affects the coherency of Papa Jupiter's speech.
The Anchor Bay DVD (even in the UK) is completely uncut: gutted dog, gun in mouth, Bob's head and all.
The original version of the film was given an "X" rating my the MPAA. Several of the most violent/graphic moments were edited out to secure and "R" rating.