Well, Wonderful End of the World is neat but I missed the rolling from Katamari
I might work on this some more later, but I've gotta fine-tune the processes of attaching things to the ball correctly and my formula for determining whether you're big enough to pick up a particular object, before I get concerned with fine-tuning simple variable changes such as movement speed.
Rather than simulating every single object attached, I'm using an invisible spherical hitbox so I also gotta work on how I alter the size of the ball for each object added.