I found your demo here: Platformer extension demo - Arcade - Microsoft MakeCode
Based on this idea: Slope collision test - Arcade / Game Design - Microsoft MakeCode
I made this.
I know it is not perfect, as the sprite bounces up and down on certain parts of the slope, but good enough for me (and frankly, also for my little knowledge of trigonometry 
). I am happy with the result and also how the sprites move at the correct speeds. 
