Here is the full list of all 21 Raji: An Ancient Epic achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Complete the level "The Deserts of Thar"
Complete the game
Complete the level "The Dream"
Complete the level "Land of the Mystics"
Find all Favor orbs in Land of the Mystics
Find all Favor orbs in the game
Listen to all the stories from the Mystical lore
The Ice elemental, a gift from Lord Shiva
Find all Favor orbs in The Fortress of Jaidhar
Complete the level "Hiranya Nagari"
Find all Favor orbs in Hiranya Nagari
Nandaka and Srivatsa, the sword and shield of Lord Vishnu
Learn about all the avatars of Lord Vishnu
Listen to the complete story about Garuda
Complete the level "The Fortress of Jaidhar"
Learn about Shakti, the primordial cosmic energy
Sharanga, a mighty bow, granted by Lord Vishnu
Learn about all the nine avatars of Goddess Durga
Complete the level "The Ruins"
Listen to the complete story about the birth of Goddess Durga
The Trishul, granted by the Goddess of War, Durga