I first tought that a 2D scene would do the same work as the 3D collect part but easier, but from my feelings instead of logic, I stayed more immersed when switching to the 2D cauldron part actually. It also looked and sounded nice. I'm surprised.
The cauldron part was sometimes frustrating but also fun. There's just the big amount or rocks that felt more like I was making cement than a brewage...
My comment could sound like mixed feelings but I actually really like its gameplay and uniqueness. :)
Only that extremely floppy ass expansion, not even visible if you don't hide the UI, disappointed me.