Guess a six letter word, and you'll be scored on the number of matching letters. Keep guessing and try to get the number toward 6.
When making a guess watch out for blue letters which show that you've previously used that letter, and red letters showing you a letter was used in a zero-scoring word:
State { last_play: 0, last_win: 0, streak: 0, highest_streak: 0, wins: 0, losses: 0, last_playing: 0, guesses: [], invalid_word: None }