Full list of all 12 Black Knight Sword achievements worth 400 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
Clear stage 1
Read every tutorial board
Use a magic attack on the bread
Game over, 50 times over
Clear stage 5
Finish the game in hard mode
Finish the game without ever entering the shop
Finish the game without dying
Clear Arcade Mode
Finish every mission in challenge mode
Collect all the cat head grass in story mode
Watch the end credits