Hi there. This is Mark from Game Maker's Toolkit. You may have seen my YouTube videos about game design (or joined the GMTK Game Jam here on Itch.io). Well, how about a video essay that you can play?
In this short game, you’ll get to see, first hand, how platformer characters are designed as you use the toolkit to change and adjust over 30 variables that drive the hero’s movement.
Please give it a try. It's free, playable in browser, and has Windows, Mac, and Linux builds.