extract-tuning.txt
Here's my game code: <paste>

Pull every magic number that affects how the game feels into one
CONFIG object at the top. Speeds, gravity, cooldowns, damage, spawn
rates, costs, thresholds.

For each: a comment saying what it does to the feel, and a sensible
range. "Higher = floatier jump" is what I want, not "jump strength".

Leave genuine constants — canvas size, array indices — where they are.
Tell me which you decided weren't tuning values, and why.

Then: how do I expose these as on-screen sliders during development so
I can tune while playing?

Tuning while playing beats tuning while reading, every time. Feel is not something you can reason your way to from a number.