This was super cute, a nice tribute to childhood games that brought me back a bit, even though I never played this particular game, I played games altering the rules before.
One of the few things I would change is the drag sensitivity, it was a little too squirrely.
I think this could be refined into a more full game, keeping the flicking mechanic and most of it's loose rule-making fun, but adding just slight qol mechanics, like having a toggle option to have bottlecaps teleport to the other side of tunnels if the caps touch the red circles, and most assuredly letting players draw out their own courses.
I could see a version of this made on Table Top simulator for a lot of fun.
This was a great time trip!
Flick mode is the only way to play it!