Loved the Demo. The aesthetics, sound effects, and UI juice are just right.
2 things I encountered:
1. When you are removing letters from your word by clicking on them, the submit button moves. I accidentally submitted a word by clicking in the same spot where a letter used to be, hitting the submit button that now moved to that location, and was unlucky enough that the shorter word was valid, thus submitting it unintentionally. Ideally the most important buttons would stay in predicable locations.
2. A more accurate prediction of expected points would be nice, currently the estimate given seems nowhere close to the end result. Even if you don't want to show the effects of scrolls, it would be nice to the expected points if you had a purple gem which doubles other gems in your word.
Great work!