Here is the full list of all 16 Kneedle Knight achievements.
Finish watching the ending story sequence.
Collect all of the cheese pickups in Levels 1 through 3.
Collect all of the cheese pickups in Level 1 (Dungeon).
Collect all of the cheese pickups in Level 2 (Tea Room).
Collect all of the cheese pickups in Level 3 (Laboratory).
Complete Level 1.
Complete Level 2.
Complete Level 3.
Complete Level 1 within 5 minutes.
Complete Level 2 within 5 minutes.
Complete Level 3 within 5 minutes.
Finish watching the beginning story sequence.
Complete all three levels without killing a single Candle.
Finish watching the ending credits.
Get all of the achievements.
Knocked back two fireballs at once