Here is the full list of all 20 Bosorka achievements.
The base game contains 15 achievements, and there is 1 DLC pack containing 5 achievements.
Collect 20 thousands gold coins
Kill 5 elite monsters
Research a spell in the well
Fall into the sacrificial pit in Whisperer Grove
Collect 13 souls
Die from the location boss
Free 5 companions from the cage
Open all chests on one level
Defeat the location boss
Collect 30 runes
Kill 10 enemies with a broom
Kill 5 enemies with less than one heart
Kill 100 enemies
Complete one level in 7 minutes
Complete the game for the first time
Burning, kill three Litavets with a dash during one run
While under the Curse of the Old Rat, kill any boss using the Viper's broom ability
While under the Curse of the Four Winds revive 10 fallen companions during one run
Free all imprisoned demons across all locations during one run
Complete the game under the Curse of the Black Book