These are all great ideas that should be added in a later version. I'll have to think of a clever way to add a force indicator as I don't want it to be too easy to replicate the perfect shot.
how about some subtle camera zoom and a post-processing vignette that fades in the stronger your shot is? That way the player can tell roughly how strong their shot is going to be, but it's vague enough to not be repeatable.
