Well, it looks like you have a basic battle system in place which you can build off of. A few tips though. First, don't use text as buttons. It's hard to click on them sometimes. So put a box behind the text on the buttons. Next, it looks like you're planning to pull an Epic Battle Fantasy where the game is just one battle after the other, but this does not a good RPG make. So you should sit down and come up with a good story to go with your game. It doesn't have to be elaborate, maybe just a few cutscenes between each stage. Lastly, don't make it so that one wrong move will cost you the battle. Games should be challenging but not to the point where it's less fun and more of a chore to win.