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