I found out that after beating the Rabbit Cup and coming in first place you unlock a hidden/secret Augie Doggie's Cup, which can be manually unlocked with this password:

YELLOW, GREEN, PURPLE, RED, RED

If you enter those colors at the bottom of the menu it will make the new cup appear.

I think this should be added as another category along with Gorilla/Turtle/Rabbit given how easy it is to unlock with the password.

Though if this were to be added I don't think All Cups should change and that it should remain as the three default cups.

I will check it! Thank you for saying it. (Category was added)