Hey there! Itch's built-in ratings system is similar to Amazon because only 5 star ratings really count while browsing games. Since ratings affect people making a living, it's polite to leave the maximum rating if you like something!
For the jam, though, I named the feedback area "Rank" and intended for the full 5 star spread to be used, so we can find out who the winner is. I'm pretty sure jam rankings are private, so you won't be spitting in anyone's face!