Here is the full list of all 20 Shovel Knight: Specter of Torment achievements.
Beat the game within 1 hour and 30 minutes.
Without replaying any stage or minigame, finish the game while holding 60000 gold or more.
Destroy every possible checkpoint in the game.
Emerge unscathed from a battle with any boss besides Black Knight!
Finish any main stage without taking damage.
Finish New Game Plus.
Obtain all Darkness and Will Upgrades from within the stages.
Finish the game without acquiring any Will or Darkness upgrades.
Use only curios to defeat any Boss Specter Knight is trying to recruit!
Complete any Order of No Quarter recruit stage using your standing slash 10 times or fewer. Dash Slashes are ok!
Speak with every recruit within the Tower.
Acquire all armor, curios, and upgrades.
Find and return all Red Skulls.
Reminisce and remain still on the Tower's rooftop for 30 seconds.
Finish the game.
Land all 3 rail tricks in a single grind.
Find Specter Knight's secret room!
Fill both of the tower's mysterious jars.
Chain together multiple targets with dash slashes 500 times.
Reach the top of the climbing mini game.