Tests cases for a word guessing game

I'm writing some test cases for a word guessing game. Similar to hangman whereby the players can guess the word. The player has only 4 guesses and on each incorrect guess the computer will indicate how many letter positions are correct.

I've come up with some tests cases to test this game but feel like i've missed alot out. What tests would you run on this game? And would there be a way to automate the testing?

    Difficulty (1-5)? 3
SCORPION
FLOGGING
CROPPERS
MIGRAINE
FOOTNOTE
REFINERY
VAULTING
VICARAGE
PROTRACT
DESCENTS
Guess (4 left)? migraine
0/8 correct
Guess (3 left)? protract
2/8 correct
Guess (2 left)? croppers
8/8 correct
You win!