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