Actually, I better tell you so nobody gets disappointed later; I ended up choosing not to use ball materials. It worked very nicely from a puzzle point of view in WaDF, but it doesn't work that well in a more "open" game world like this. Basically, a game have something of a will on it's own, and sometime I need to go a different direction that I originally planned because the game needs it. I decided that instead of achieving complexity through the ability to change between powers, I wanted complexity by a single movement type with more depth. If the hook in WaDF were the ball materials, the hook in this game is how you can make a certain move where you chain uses of both characters to get the right momentum to reach a specific place. It's probably a little bit harder to learn, but it is very satisfying when you get the hang of it.
In either case, even though you get a ball movement, don't expect everything from WaDF, this is still a new game that plays very differently. What you can expect for sure is a huge non-linear world with a lot of variation and atmosphere, and more exploration than in any of my previous games.