Creator Backlash: Aaron Sparrow, who started the comic book with the storyline for "The Duck Knight Returns" hasn't really been satisfied with the direction Ian Brill eventually took the series, culminating with the issues within Dangerous Currency, with him and artist James Silvani having written their own ending for said crossover.
Aaron Sparrow has since rewritten much of the old Boom material for it's 2015 reprint and is planning to remake Dangerous Currency as the start of a new ongoing.
Dan Castellaneta (Krusty the Clown, Homer Simpson, Grampa Simpson, Groundskeeper Willie, Hans Moleman, Arnie Pie, Pedro the Bumblebee Man, Mayor Quimby, Barney Gumbel, and Jeremy Freeman note that pathetic teenager who works at the Krusty Burger, both movie theaters — The Springfield Googoplex and The Aztec Theater, the supermarket, and Phineas Q. Butterfat's Ice Cream Parlor) as Megavolt
Speaking of Simpsons voice actors on Darkwing Duck, Edna Krabappel [the late Marcia Wallace] voiced Taurus Bulba's secretary.
In Mexican Spanish Darkwing (as well as Bushroot) is Scrooge McDuck, of all people. You could close your eyes in his conversations with Launchpad (who maintained his voice) and often you felt back in DuckTales!
In both Spanish dubs (Mexico and Barcelona), Darkwing sometimes lapses into Simba.
Keep Circulating the Tapes: The final 37 episodes (that is, everything starting from "Inside Binkie's Brain") are not on DVD, and are unlikely to get an official release anytime soon. However, three of said episodes ("Negaduck", "Tiff of the Titans", and "A Brush With Oblivion") have previously been released on VHS.
In Poland, it was aired in 1994 on TVP 1 (the first channel of TVP, Poland's equivalment of The BBC), but they aired only 7 episodes. When they aired the 7th episode, TVP took the series off air and replaced it with Goof Troop, because according to KRRiT (Poland's Media Watchdogs) this cartoon couldn't be watched by kids.
In most dubs Darkwing and Negaduck share a voice actor.
In Mexico, Arturo Mercado is Darkwing, Negaduck, and Bushroot. Diana Santos is Honker, Binkie and Tank.
What Could Have Been: As mentioned in Shout-Out entry on the main page, the original pitch for the show was very different. It was originally going to be a James Bond spoof called Double-O Duck, with Drake Mallard as a globe-trotting spy working for SHUSH. All the villains were going to be agents of FOWL (Fiendish Organization of World Larceny) with Steelbeak overseeing them as the show's big bad. Eventually the concept was combined with ideas from a superhero-based DuckTales episode and became Darkwing Duck. DW sometimes does missions for SHUSH as a freelance agent, so some of the spy elements survive. FOWL occasionally pops up but only two of the show's dozen or so recurring villains actually work for the organization, and it's run by three unknown shadowy figures.
Disney's merchandising division never got the full memo about the change, so most of the show's merchandise portrays all the villains as FOWL agents with Steelbeak as their leader. The Darkwing Duck NES game famously bases its whole plot around this concept.
"Double-O-Duck"? That was the name of an episode of DuckTales where Launchpad went undercover as a spy. Heck, Launchpad's Tuxedo and Martini was the basis of Derek Blunt's costume. "Double-O-Duck"/Double Duck latyer became Donald Duck's spy name in Donald Duck comics.
FOWL was in that episode, and its leader at the time was apparently Killed Off for Real, letting "High Command" take over by the time of Darkwing Duck.
The writers came up with the idea of a spin-off set Twenty Minutes into the Future, featuring Gosalyn as either a teenager or young adult, and featuring her own superhero alter-ego, Quiverwing Quack (who had previously appeared on Darkwing, and was a Green Arrow parody, right down to the trick arrows). It never got past the planning stages.
There were also several episodes planned that never got produced, due to ABC and Disney cancelling after season 3, but before season 4 made it past planning including the return of such baddies as Paddywhack and the original NegaDuck. The cyborged Taurus Bulba has made a reappearance at the end of comic #3.
With the series undergoing a revival by way of a return to the comic book medium, it's possible that most of these plans will be given a second chance.
Indeed, it looks like Paddywhack is coming back around issue #8...