It seemed to have been a curse of good 80's films with exploitable theme to sink ever lower depth, cheaper effects and amateurish actors, the more Roman numerals one would attach to them. Remember "RoboCop"? Half-decent sequel, a third part that reeked. "Warlock"? Cult-classic first part, mediocre second, unwatchable third. "Highlander"? "American Ninja"? "Batman"? The list could go on.
"Scanners III" neatly fits into that mould; the original being a true classic, the second part a cartoonish but enjoyable romp and the third, well, it makes you glad they didn't film a third "The Fly"-film (although an African video-vendor tried to sell me a bootleg of "The Fly III", but that's another story).
Short story shorter: a pair of Scanner siblings, one good one who has learned to control his powers and his evil sister, who chemically boosts her powers in order to take over the world, battle it out with the usual Scanner abilities. The powers are stronger, the theatrics – mostly due to the lack of acting abilities – are even more theatrical but the human-factor of the original "Scanners" has left the franchise forever. The original Scanners were mostly portrayed as average people who had to deal both with a power and a disease. One felt for their misery and, through the minimalist approach of original director David Cronenberg, one could almost imagine those people were troubled, but real people. The Scanners of this film seem like comic book heroes (and villains) who might well have fitted in with some cheap TV-production of "Super Friends".
This film isn't even cartoon anymore; it's the purest of C-grade straight-to-video Dreck. But there's the golden 80's principle and the producers had a concept there: most of the fans still slavishly rented or purchased the film, same as they did with "Scanner Cop" and "Scanner Cop II". I know I did. And I watched all the RoboCops because, you never know, there might be a shine of former brilliance to surface yet. People, we've all been conned. Will I go watch another sequel or a remake? Sure, I'm an incorrect able sucker for franchises and plan to stick to that – one can always complain later.
And by the way: when in East-Africa and they somebody tries to sell you a video-copy of "The Fly III", don't buy it! It's just a cheap horror-film, left on the cutting board table somewhere in Hong Kong, about a woman who stings herself on a mutated plant and gives birth to a giant killer-bug. Trust me: I know what I'm talking about! Four points for the film, one for nostalgia.