The Legendary Starfy
Note: This game is also titled Densetsu No Starfy: Taiketsu! Dire Kaizokudan.
Successfully complete the game by finishing World 8 to unlock the "Boss Mode", "Gachapon", and "Sound Test" options as well as World 9. To access the new options, press R at the level selection screen.
Successfully complete Boss mode (Big Bossdown) with either Stafy or Stapy with a time less than 9:00. World 10 is a series of time attack levels that includes a new Boss. To face the new Boss, you must complete Level 10-1 with a time less than 0:45, Level 10-2 with a time less than 2:20, Level 10-3 with a time less than 3:50, Level 10-4 with a time less than 2:10, Level 10-5 with a time less than 2:50, and Level 10-6 with a time less than 2:30.
Successfully complete the game two times to view an alternate ending.
Play on your birthday to see an alternate introduction screen.
In Hotcha Springs (Level 2-1), get to the part where there is a little rock below the door you just entered, little white fish to the top left corner of the stage that inflate when you touch them, and a line of fish to each side of you. Start by going to one line of fish and using the spin attack to take out the line of them, then go to the other side and take out that line. Keep repeating this, going from one side to the next, until you get as many pearls as desired.
The background music of the "Abilities" screen is the music from the Special World of Super Mario World.