Hmm I am cannot claim to be that experienced with game polish myself, but some easy animations to make it less static could be doing a squish to the character (i.e. squishing down the character sprite and then restoring the scale again over the course of a few seconds) basically a cheap idle animation. The goal could have some sparkles or something to make sure the player knows that is the goal. Also I would reference winning animations for puzzle games that have a similar "three star" system - they make it feel awesome after every success (usually I see a separate screen for winning for example).