This is to make it clear for the people, especially people who didn't like the episode.
Q: What?! This was made in Flash?!!!
A: Yes. Yes it was.
Q: But why?
A: Cause Craig thought it was a really useful tool for animation, which is why he used it on Fosters. He wanted to use it with PPG too.
Q: What's with all the dumb jokes, references and silliness?
A: Craig wanted to make the episode as silly as possible, since the Movie was full of seriousness. You got to admit though, lots of the jokes gave you lulz.
Q: WHY ARE THEY SPEAKING SO FAST?!
A: Actually, not a lot of people know this. But the Episode was originally more than 24 minutes long. The limit for Episodes were 22 minutes. So they either had to cut out a few parts, or speed up the episode by a bit. They decided to speed up the episode. The original 24 minute version can be seen in "PPG The Complete Collection" Boxset. It makes much more sense to watch the original than the CN version.
Q: Everyone is acting like 5 year olds. Especially Mojo Jojo & The Professer. Why?
A: To make it very funny. Maybe Craig should lay off Foster's for a while XD
Q: Where did they think of a plot like this?
A: The episode was actually based on one of the original "Whoop*ss Girls" episode's by Craig way back in the early days, where Him (known as just "The Devil") challenges the Girls to a race to claim the Key of the World. The animatic of this episode can also be seen in "PPG The Complete Collection" Boxset.
Q: You think after this, they'll make a 7th season?
A: No. Craig realizes he's only repeating the same thing to story plots: Monster, Problem, Solution. Monster, Problem, Solution. Monster, Problem, Solution..... He wants to stop this and work on other shows. It doesn't mean he doesn't love PPG anymore (Why did you think he made this episode?), he just wants new fresh air.
Q: Aww. Come on! How come no new season?!
A: I hope for a new season someday too. But that day won't come soon. He's busy finishing up Foster's and starting a new thing called: Cartoonstitute http://en.wikipedia.org/wiki/Cartoonstitute
Q: Well, least I could do is get "The Complete Series Boxset". Where is it?
A: It's really scarce to find in stores. In fact I found only one Copy at one Best Buy.
Q: It's not at Best Buy, Target, Walmart, etc.
A: If you have no luck finding that precious gem. Get it Online. Amazon.com is the best.
Q: Any future for PPG?
A: Yes. Legacy my good friend. Legacy.
Thanks for reading! If you have any more questions related, just ask.