Hi Tassanee,
It's a great idea.
First: You can create a new state in the letters that are selected, and until a button is clicked, the solution doesn't appear, the ones that are OK, they would be in the correct state and the others would return to the normal state. You can have the button disappear once you have clicked a certain number of times.
Second: Regarding the score, it can be done, you should have a numeric variable that takes the value of the Score of the student of the results page. Then it should add a value to this variable that, with conditions, it can make it different in function if it has gotten it in the first or second attempt.
Once this is done, you should reference that variable on the slide.
Probably we will try to do this, once we have it. We will share it.
Thanks!