Here is the full list of all 22 Building Block Heroes achievements.
Complete the Tutorial.
Use Heatwave's ability.
Use Ice Queen's ability.
Use Airhead's ability.
Use Dirtbag's ability.
Complete a level with a friend.
Defeat a boss with a friend.
Defeat the first boss.
Defeat the second boss.
Defeat the third boss.
Defeat the fourth boss.
Defeat the fifth boss.
Defeat the sixth boss.
Defeat the seventh boss.
Defeat the eigth boss.
Defeat Rupert.
Beat the game with a time limit enabled.
Beat the game with a time limit of 10 minutes or less.
Beat the game with a time limit of 5 minutes or less.
Beat the game in Hard Mode.
Beat the game in Breaker Mode.
Beat the game in Connect Mode.