it introduces variables on the 93th slide and uses the site's functions until then. I'd say it's more like an illustrated codeguppy js course than a general js course.

I think if your market is mostly kids it might be easier for them to be able to click on the shapes/sprites and have the parameters UI open up for that clicked object as you get used to this in many apps. E.g. they could tweak the parameters "x, y, size, fill, etc" and see real time how the code changed. Or have the parameter name hover over the parameter like in some jetbrains products.