Hey, It's That Voice!: The celebrity voices were usually played up, but some of them required a more careful ear: for example, Tom Cruise was Captain Planet for the first few episodes before leaving the series.
Linka is Kath Soucie, better known as Tish from The Weekenders, and has an extensive voice acting career in both animation and video games.
Fittingly, the German dub had Captain Planet with Dean Cain's regular dubbing voice, thus making him anothersuperhero. Spain, however, has Kwame as the 1948 Superman.
as Rigger, Meg Ryan as Dr. Blight, James Coburn as Looten Plunder, and Ed Asner as Hoggish Greedly. Oh, and a guy named Tim Curry was the voice of MAL after the first season. However, many of these celebrities only voiced their characters for the first season and cheaper replacements handled them for the rest of the show's run. For example, Sly Sludge was given to Jim Cummings and Dr Blight was given to Mary Kay Bergman.
Zarm, the god of chaos and pollution, was Sting, then David Warner, then Malcolm MacDowell!
What Could Have Been: In one episode we actually see that under very specific conditions, it was possible to have a Captain Planet without all five of his elemental superpowers (in this example he only had the powers of Earth and Heart, due to their ring-bearers being trapped on a spaceship). This caused the usual Deus ex Machina Captain Planet to actually think strategically as he couldn't do everything he normally could . . . . sadly, this concept was never revisited beyond this one episode, but various partial power Captain Planets could have been an interesting concept to expand on.
Miscellaneous trivia
A producer was unsatisfied with a number of facial designs for the Captain until one of the artists finally submitted the producer's face as a joke... and to make a longer story shorter, that is why Captain Planet looks like Mr. Boxer (though one would suspect the latter never had a green mullet or the superhero musculature).
The episode "Whoo Gives A Hoot" had Looten Plunder win at the end.