The cell shading works.
It always is facing away from the screen, so far.
Pics in a second.
EDIT: Forgot, I rigged the head to be singlebound. The non-singlebound stuff still looks nice though.
I might've messed up in the the testing model I chose. A lot of it is still singlebound.
DOUBLE EDIT:
Okaaaaay. Maybe the head isn't singlebound. The Cellshading on the head works, but the metal effect doesn't.
Odd.
This was a quick rig, anyway. There's bound to be some stuff that's wrong. (I mean, the entire left arm is rigged to the elbow. Oops!)
EDIT 3: (Be glad I don't double post!)
According to my observations, an object does
NOT need to be singlebound to be able to utilize cell-shading correctly, which is lucky for you Xiggah. The reason I thought the non-singlebound object wasn't working right was because of the shape. Certain objects look the same from all directions, which would make you think they don't work. They do.
All in all, you guys are lucky. Cell shading works PERFECT.
EDIT 4:
So I took my first hack, Amy Rose and (among other things) added Metal and CellShade.
Amy's model is most likely meant to be Cellshaded. It has no shading directly worked into the textures.
As it turns out, the things that hold Metal adding back don't affect Cellshading, meaning Single-Bound objects can have perfect CellShade without perfect Metal.
A little bit of experimenting and we could probably solve the imperfect Metal problem as well.
I tested on two different stages to make sure nothing was messing up. The results are below.
Pictures: