Wow, you've been working on a lot of things lately. The first thing I realize is that I need to add some security to my code so it's not so easy to manipulate. Don’t get me wrong—I’m not upset that you did it, especially since it was meant to help, but it’s definitely something I need to keep in mind for the future.
The translation isn't very accurate, especially when it comes to more technical stuff, but if I understood correctly, you're suggesting that I stop using a CharacterBody2D and instead use an Area2D as the parent node to optimize things?
As for Mimi giving more points based on luck, that’s actually an idea I’ve had for a while but haven’t implemented yet. Regarding the slime girl, the original idea was that she'd move from one side of the map to the other, absorbing objects, and if you caught her, you’d earn what she had collected multiplied, and if you missed, you’d lose some coins. That said, I really like the idea that whether you win or lose, since she's a slime, she could "lubricate" you and make it easier to raise the multiplier for a few seconds.