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.
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