Development Hell: The live-action movie has been in this since its announcement in 2011.
Doing It for the Art: Ted Turner was genuinely angered by pollution and abuse of natural resources, and commissioned the series as his way of doing something about it.
Fake Russian: Linka's American voice actress, Kath Soucie. "Linka" isn't even a valid Russian name. It could conceivably work as a nickname. You might call a girl named Galina "Linka", for example, but, as a proper name, it's more West Slavic.
While her home country was never specified in-series, it is suggested to be Ukraine, due to her being from a mining family (mining, especially for coal, is one of the largest employers there) and also as a nod to the then-recent Chernobyl nuclear disaster.
Keep Circulating the Tapes: a few VHS tapes containing 1-2 episodes were released a ways back but they are now out of print and very hard to find. Shout! Factory did release season 1 to DVD but never released the rest of the series due to low sales.
The trope was finally averted in November 2017 when Madman Entertainment and Cartoon Network worked together to bring the complete series to availability on DVD, but only in Australia and New Zealand.
The entire series can now be bought off iTunes.
Name's the Same: This show's Duke Nukem shares a name with the video game series Duke Nukem, which stars a human by the same name.note In fact, Apogee changed the first Duke Nukem game's title to "Duke Nukum" as they believed there would be a potential trademark issue, though they were able to switch back as it never became a problem.
James Coburn was replaced by Ed Gilbert as the voice of Looten Plunder in season 4.
David Rappaport was the voice of MAL for the first four episodes featuring him and Dr. Blight, but was replaced by Tim Curry for the rest of the series because he passed away while the first season was still in production.
Posthumous Credit: MAL's original actor David Rappaport died while the first season was still in production and had only recorded dialogue for four episodes prior to his passing. In spite of this, the show's first season still acknowledges his involvement in the end credits.
Prop Recycling: The first episode of had Hoggish Greedly attack Planet with a hose that spewed toxic waste; it looked very similar to the neutrona wands on the Ghostbusters' proton packs (both series were made by DiC, although Planet moved to Hanna-Barbera later on).
Screwed by the Lawyers: Captain Planet has an odd distinction to why he's been mostly used in parodies and stuck in Developmental Hell and it is mostly due to a legal decision. Captain Planet was originally created for Turner by DIC but when Turner bought Hanna-Barbera the rights were transferred over to them to produce new seasons but legally Captain Planet was never merged into their library. In 2001 when Time Warner abandoned the idea of merging Hanna-Barbera and Warner Bros Animation into one entity they split the Cartoon Network Studios off as its own entity under Turner. The rights to Captain Planet actually went with them instead of with the other HB and MGM brands. As a result Warner Bros has had to deal with Cartoon Network on any possible Captain Planet projects and CN has often soured on new ideas as they came out, as seen below. This is of course also why he was the only non CN original character in Cartoon Network: Punch Time Explosion. Now in 2019 with AT&T removing the separate Turner management, this is now no longer an issue.
What Could Have Been: A live-action movie was in development in the mid-90s; titled Planet or Dark Planet, it would've taken place After the End and would've been significantly Darker and Edgier. However, the script "fell through the cracks" during the Turner/Time-Warner merger and it didn't happen; they've been trying since, though they may have abandoned those efforts since Paramount is trying to pick up the rights, attaching Leonardo DiCaprio as producer.
The executive producer of the show, Nick Boxer, once pitched the idea of removing Captain Planet, the show just being the "Planeteers". But Ted Turner rejected the idea, so the team attempted to find way to keep the Planeteers empowered while Captain Planet did the heavy lifting. One way they did this was having the kids rescue Captain Planet himself when he is downed from time to time by the villains. So in a way, while Captain Planet does do the heavy lifting and rescues the Planeteers, when Captain Planet is down, the Planeteers, without their powers, must work together and rescue him as well. So in a way, the producers attempted to avert a Broken Aesop.
The exaggeration of the villains to the point of cartoonish supervillainy meant that children watching the show would not be troubled by their parents if they worked in a polluting industry. Loggers, for example, are not monsters, but had they been portrayed as such, that could have caused confusion and conflict, so the bad guys had to be as over the top as possible. The fact loggers are portrayed as complete monsters by some Animal Wrongs Groups who take the show as a holy writ for environmentalism suggests that as exaggerated as it was Strawman Has a Point.
Unfortunately, this may have backfired, since the unrealistic and over-the-top nature of the villains has made them a frequent source of Snark Bait for adult viewers who are more knowledgeable about environmentalism.
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).