Thanks Josh!
You don't think shaking a textbox and playing an annoying sound is enough discouragement? Just kidding, I know what you mean but I couldn't think of a good way to do it without introducing something like player lives/health and the UI is already a bit busy. I'd rather have even less things shown in UI than it does currently.
Good feedback regarding the difficulty too - I found it hard to balance/understand the difficulty in this game since I was playing it so much. Once you remember the valid words the game feels a lot different/easier and I don't know how I would playtest it through "fresh" eyes.