After learning how to move the raindrops, I showed Grey how to use the hollow sliders. Each slider has a hole at the top to drop food through, and once your cat moves the slider over one of the compartments, the food drops out the bottom. Grey struggled more with this level of the puzzle, but having the food sitting in there, available to sniff, definitely motivated her to figure it out.
There's also the wheel up top, which covers a bunch of food slots. This took Grey the longest to figure out, but after watching me spin it a few times, she gathered that it could move and eventually pieced together how to shift it with her paw on the textured top.
Image Source: POPSUGAR Photography / Alessia Santoro