No missable achievements (plus 14 unknown)
Sign in with Steam or Xbox to track your progress, and:
Acquired the Cerulean Aura.
Acquired the Crimson Aura.
Acquired the Springheel Boots.
Acquired the Spider Gloves.
Lost the game in any mode.
Won the game in any mode.
Traversed every room.
Collected every money bag.
Won the game in any mode with a 100% rating.
Won the game in any mode in under ten minutes.
Won the game as a cat.
Won the game while wearing sunglasses.