To get all the bonus items in Arcade mode, which include the four other tracks (Autumn Ring, Deep Forest, SSR5, and Grand Valley Speedway), all the other cars (Toyota, Subaru, Dodge, and TVR), the ending movie, and Hi-res GT Mode, you have to beat every single track with each type of car (A, B, and C) under all three modes of difficulty (Easy, Normal, Difficult.)