Here is the full list of all 27 Bloo Kid 2 achievements.
Get all 360 stars
Finish the game on "Nightmare" difficutly
Beat the game in Time-Attack mode
Finish the Boss-Rush mode
Finish the game on "Normal" difficutly
Finish the game on "Hard" difficutly
Finish the game on "Easy" difficutly
Beat the World 5 Boss without taking damage
Get 300 stars in total
Beat the World 4 Boss without taking damage
Get 250 stars in total
Get 225 stars in total
Get 200 stars in total
Beat the World 3 Boss without taking damage
Get 175 stars in total
Get 150 stars in total
Get 125 stars in total
Beat the World 2 Boss without taking damage
Get 100 stars in total
Get 75 stars in total
Get 50 stars in total
Beat the World 1 Boss without taking damage
Jump on 15 enemies in a row
Jump on 10 enemies in a row
Get 25 stars in total
Jump on 5 enemies in a row
Jump on 3 enemies in a row