Spiral, thanks. Your ideas are awesome! ^^
The game is indeed set in other parts of the R1 valley ( actually the parts to the right of the R1 world map ). Candy Chateau is certainly in it, so that's one of the 6 worlds for certain. Still, it'll be a lot different to the one in R1, as you'll actually get to travel INSIDE it now.
The magical, but dark forest ( with waterfalls so it's a bit like the world in the R2 beta ) is almost certain to be used as a first world ( I even have a name for it to parody R1's Dream Forest: Nightmare Woods!

).
A glacier world could be used as a second world, though I don't know yet. It's a really good idea and it would fit the story well, but I don't know... I'll think about this more.
A mountain world isn't certain yet - maybe something else as a third world where I could place a volcano at the end ( for the lava level, which is kinda necessary for the story and also just because I love the lava levels in R2 )?
The 4th world can't be a mechanical world, that's for sure, since there are already some pirate levels throughout the game, one in each world, actually. And the real "Robo-Pirate base" is already in the story, just before you enter the castle in the last world. It's crucial for the story that it's there and nowhere else, because something happens there. So yeah, I don't know about this world yet. I'd love this world to take place somewhere in the sky though, or at least the last level, because for Picture City ( which was going to be the 4th world ), it was planned that Electrix would cross a rainbow, and at "the dark side of the rainbow", it'd start to fade and he'd fall right into the water, where he'd be captured by Space Mama ( in viking outfit ^^ ) and her pirates.

I'd like to keep this ( but put someone else instead of Space Mama, and maybe change the pirates to robo-pirates ). Well, at least he'd have to fall into the water, maybe the fight could take place in the sky. But he has to fall into the water, because there's a swimming level next, and then a level that takes place in some kind of submarine, overrun by antitoons.
Normally, he'd escape and end up on the shores right in front of the Caves of Skops then, but this could change. Spiral gave me an awesome idea for the 5th world. What if he escaped, and instead of ending up on the shores right in front of the Caves of Skops, he'd end up in the belly of a gigantic monster fish?

Because of all the creatures the fish swallowed, there'd even be a village and a bar ( Joe's bar! Because Joe is also necessary for the plot... ) inside.
There'd be something evil inside the fish too though, something that has always plagued the village and Joe's bar ( well, at least since the fish swallowed it XD ).
Killing it would make its 'blood', lava/acid/some other thing that's also deadly, kill the fish ( but also make you run ), and, you'd end up in a pool of water... with a peculiar taste. It tastes sweet. You're in Candy Chateau! XD
I could still just keep the R1 worlds too, but I think it'd be a lot more original if I changed the worlds, and the enemies and bosses. There'd be just so much more I could do.
