Let's be honest, a game that's just black and white is pretty boring to look at. If someone wants to change up the background, font, button styles etc that would be great.
Twist: We need to implement a twist button that shuffles around the words that have not been selected yet as seen in the game version here (http://en.gameslol.net/text-twist-644.html).
Enter: Another button to add would be
Last word: Keep a reference to the last word entered and put that in the
Clear: This one is pretty self-explanatory, just clear the current words submitted.
I would recommend keeping two separate array/ArrayList for letters not entered and entered.
Maybe also either a string or another array/ArrayList reference to the last submitted word.
Another improvement that would be nice to implement than towards the end would be music that plays during the game and sound effects while the action occurs such as a button being pressed.