Here is the full list of all 9 Enworden achievements.
Played a palindrome
Played a word that starts with and ends in G
Used all letters of the alphabet during a game.
Played a 10+ length word.
Played the same word 3 times in a game.
Played the same word twice in a combo.
Got all stars in the main campaign.
Played a level with 2-letter words only.
Selected all tiles on the board simultaneously.