Wow, this is a lot of fun! Really polished, great gameplay idea and implementation, and beautiful pixel art. And as a cat person, I can only approve of the character and its reasoning :P
I reached the Moon in 15 runs. The Linux build works great, including with my touchscreen (BTW you exported Debug builds, so it's not optimized, but it still runs fine). I could definitely see myself playing this on my phone too :)
My only criticism would be that things can get very busy on the screen when you're fast, and it can make it hard to see the mouse cursor or even the cat. That's part of the game's difficulty, but maybe having a custom, bigger mouse cursor would help make it more distinctive. Or tweak the `+1` fish labels to take slightly less focus, while staying juicy.
One tip on desktop, you can set the mouse mode to `MOUSE_MODE_CONFINED` with Godot, so that the mouse cursor stays visible but can't leave the window. Then it's good to put it back to normal maybe on the game over screens so that players can still quit the game easily if they want.