Here is the full list of all 21 Bit Heroes achievements.
Collect 30 Quest Stars
Defeat Quirrel
Reach Level 50
Collect 20 Different Familiars
Collect 15 Quest Stars
Defeat Gemm
Make a fusion
Reach Level 20
Collect 5 Different Familiars
Defeat Lord Cerulean
Collect 5 Quest Stars
Join a Guild
Add a friend
Reach Level 5
Collect 1 Familiar
Reach Level 100
Reach Level 200
Collect 50 Different Familiars
Collect 100 Different Familiars
Defeat Kov'alg
Collect 50 Quest Stars