Here is the full list of all 28 Miracle Fly achievements.
Beat "Shooter 1" at Boss Challenge
Beat "Rabbit 1" at Boss Challenge
Beat "Slime 1" at Boss Challenge
Beat "Slime 2" at Boss Challenge
Beat "Slime 3" at Boss Challenge
Beat "Rabbit 2" at Boss Challenge
Beat "Rabbit 3" at Boss Challenge
Beat "Shooter 2" at Boss Challenge
Beat "Shooter 3" at Boss Challenge
Beat "Bat 1" at Boss Challenge
Beat "Bat 2" at Boss Challenge
Beat "Bat 3" at Boss Challenge
Beat "Sniper 1" at Boss Challenge
Beat "Sniper 2" at Boss Challenge
Beat "Sniper 3" at Boss Challenge
Beat "Froza" at Boss Challenge
Beat "Lumina" at Boss Challenge
Beat "Yoruko" at Boss Challenge
Beat "Mira" at Boss Challenge
Beat "Daria" at Boss Challenge
Beat "Irvette" at Boss Challenge
Beat "Acroz 1" at Boss Challenge
Beat "Acroz 1 Devil Form" at Boss Challenge
Beat "Acroz 2" at Boss Challenge
Beat "Acroz 2 Devil Form" at Boss Challenge
Beat "Candyland" at Boss Challenge
Beat "Cosmoland" at Boss Challenge
Beat "Boss Rush" at Boss Challenge