Comment by b3orn

I implemented a very rudimentary copy of it at https://fac3.org/slingshot.html

Drag on the red circle to set angle and velocity, let go to launch it, try to hit the green circle, avoid the blue circles (planets with gravity). To try again hit "r" or reload the page to create a new random set of planets. Doubt it works at all on mobile, only tested it in desktop firefox.