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It's over 9000!
Yes, the maximum achievable score is precisely 9001, using the word list provided by OP (Github Gist).
The secret word for this game is fuzzy. You can try the following words in order: (words in the same group can be used in any order)
⬜⬜⬜⬜⬜ : 7875 words that do not contain any o...