There, after snagging all three coins in World 8 Castle, taking the last three coins in the game, I saved the princess, then spent all the coins in World 1.
Unless I missed something, a three-star winner is all I can get. I know one-star just means you saved the princess, because that’s all my brother got. I jumped straight to two stars by getting my first win with all coins. Spending it all got me the third star.
Nice game. Not disappointing, though not so hard if you’re a Mario veteran like I am.