Thanks for the feedback, we will definitely consider it when polishing the game!
I admit the ranking system is in need of reworking - there is a time bonus but it is veeery small, and the best way to get S rank on the upper and right level is to score with a ball in both goals and hitting all the rats (or to get a perfect dash many times cos it gives +50 points). The arrow critique is fair too, since it was just a debug tool we used and didn't have time to change it for the release :b