I am impressed - and frankly humbled - at the eagerness and thoroughness of this presentation. I tip my hat to you.
I'm personally fond of the idea of Juice Galaxy shedding a little of its excess 'trippiness' off in favor of forming into a functional, self-sustaining fantasy universe, and part of that would be characters having 'quests' they need you to do. Acid trips have no sense of responsibility, but sapient inhabitants of a living breathing world need jobs done, after all.
I like your idea of the cat-related aesthetic increasing arm power; however, I think it would need to be a brand new cosmetic that isn't even in-game yet, like gauntlets; a symbol like ears might make sense for increasing speed and base jump height, I think, given cats' sprinting speed and jump abilities.