Here is the full list of all 25 Legend of Kay Anniversary achievements.
Finish the game on „Nightmare“ difficulty
Finish the game on „Hard“ difficulty
Find and activate all demon portals
Upgrade your Chi Points to the maximum
Win the fight against The Dreaded Chei Ni
Upgrade your extra-lives to 9
Win the first fight against the boar
Win an extra race without collecting a chilli
Win the fight against Minister Shun, Lord of the Gorillas
Collect all the three different armour types
Upgrade your Health Points to the maximum
Win the fight against Alchemist Tak, King of the Rats
Collect all hammers in the game
Collect all Claws in the game
Win the fight against Qian Bei the Ancestor
Win the fight against Shun's Bodyguard
Win the fight against Jia-Gu
Collect all Swords in the game
Complete the second fight training lesson
Get a 20 X Combo
Get a 15 X Combo
Get a 10 X Combo
Get a 5 X Combo
Finish the first boar race
Complete the first sword training