CONTAINS SOME SPOILERS
This is one of the many horror movies that got overlooked in the transition from murky VHS to shiny DVD: it's 28 years since it last went to the BBFC for its tape release, when it was summarily cut by over a minute. Now it's been fully restored, it's in full widescreen (none of this pan and scan nonsense!), and it's an enjoyable and good-looking blast of trash/horror nostalgia for the ex-rental era which delivers on the gore and sleaze with a vengeance.
The Beast Within starts off in 1964, when newlyweds Ronny Cox and Bibi Besch break down in the middle of nowhere: he goes off for help and she's brutally attacked and raped by some kind of forest creature. Seventeen years later, their son's (Paul Clemens) worsening health sends the family back to the quiet rural town where it happened. But he's changing, metamorphosing into the same kind of monster, apparently taking revenge for crimes a generation past and ultimately sowing the seeds for further horrors in another seventeen years....
It's true that the Tom Holland script doesn't entirely clear up whether the new creature is possessed by the original, whether it's a whole new life-form (somehow derived from cicadas), or how cannibalism has contributed to its development. The Beast Within is only passingly interested in that. Far more important are the gore sequences: Tom Burman's full-on transformation effects run the likes of The Howling and An American Werewolf In London a pretty close race, but they're badly undercut by the scene running far too long. It's as if they're so proud of the prosthetics and animatronics (and quite rightly so) that they can't bear to trim them back. Elsewhere the gory kill scenes are enjoyably gruesome, including a terrific decapitation, while the two rape scenes are more than nasty enough, but feel unnecessarily graphic in this slightly more progressive age (albeit an age where I Spit On Your Grave 3 actually exists).
The Beast Within is probably not a classic, though it's certainly leagues better than director Philippe Mora's atrocious brace of Howling "sequels" (but then what isn't?). It's messy and trashy, and the explanation for its monster makes no sense, but it's well-mounted with an upfront horror score by Les Baxter, and it looks wonderful now it's in high definition and the correct aspect ratio. More importantly, it's a reminder of a time when even splattery B-movies could be well crafted and atmospheric, with believable and likeable characters, in the way that you don't see often enough these days.