Mario Sunshine is the prequel to Super Mario Sunshine, just like how Mario Bros. is the prequel to Super Mario Bros. In Mario Sunshine, saving is not an option. You can however get to the last level, Traj Mountain, where Wawabowser (the main character) ruminates on his life in one sitting. The reason for the name was that Wawabowser was eating a Mario cookie while laying in the sunshine. Otherwise, the game has 1000 absurdly easy levels where you have to lead Wawabowser through his silent day. Many people who played this game and Super Mario Sunshine got them confused, so they think Super Mario Sunshine is bad.
The shame also has a hidden bonus level. You just have to put in the Konami Code, press the "A" button 100 times, sing a ballad, and do the twist. Then a secret door appears in level 493. If you go in the secret door, you get to play the secret level where you learn the secret fact about the secret secret. I'm not going to tell you the secret because it's a secret.