The types of difficulty are the same for every game. More in the main description doc
Compared to some other games, there are 2 differences: entering valid attempts and evaluating attempts.
For the EASY, MEDIUM, and HARD difficulties, any attempt of the selected length is valid. For the other difficulties, only those attempts that actually exist in our word database are considered valid.
For the EASY, MEDIUM, and HARD difficulties, each word is evaluated separately. For the other difficulties, characters for the entire name are evaluated.