Complete the following tasks to unlock the corresponding achievement. To view your 
achievements and stats in Steam, select "Community", then "My profile", then "View 
all my games", then the game and view stats.

Achievement                 How to Unlock
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First Boss Defeated       - Defeat first boss.
First Encounter Finished  - Finish first encounter.
Second Encounter Finished - Finish second encounter.
Third Encounter Finished  - Finish third encounter.