Here is the full list of all 20 OneBit Adventure achievements.
Defeat your first boss
Unlock a profession
Prestige a character
Unlock the secret character class
Defeat Cthulhu
Pick up 100 apples from the ground
Reach 5,000 steps
Reach 10,000 steps
Throw 10,000 coins at your enemies
Craft 25 items in the stew pot
Equip all gold equipment
Kill 100 spiders as a Warrior
Kill 100 Bats as a Blood Knight
Use 100 Mana potions as a Wizard
Transcend into 100 enemies as a Necromancer
Inflict burn on 100 enemies as a Pyromancer
Deal Critical attacks 200 times as an Archer
Kill 50 Mimic Chest as a Thief
Defeat a boss without wearing any equipment
Reach level 10 Wisdom