Here is the full list of all 20 Legendary Mahjong achievements.
Complete all levels in all the temples.
Use 10 Whirlwind Tiles.
Get the highest rank.
Restore the Temple of Wisdom.
Restore all the temples.
Restore the Temple of Air.
Match 10 Ice Tiles.
Restore the Temple of Earth.
Restore the Temple of Water.
Restore the Temple of Time.
Undo 100 moves.
Match 10000 tiles.
Unlock the Celestial Gate.
Open 10 Box Tiles.
Restore the Temple of Fire.
Use 10 Magnet Tiles.
Restart 5 times.
Match 10 Lock Tiles.
Get a new rank.
Match the first 2 tiles.