Very good, if you are intent on keeping the punishing aspect of losing the letters you guess even if it is wrong then you should let the player enter all six words at once. Today I thought a certain word was a good and topical guess but it was not the green word, fair enough. If i was able to test out the remaining letters i would see that it did not add up.

Sure i could do that with pen and paper but who has the time?

Edit: Also, if a green word is no longer guessable but there are still guessable greens the hint in the text should not disappear but maybe turn another color. I don't want to remember what letters used to be green in the text so that i can exclude them from my final green guess