This is such an amazing writing program. I'm DEFINITELY going to be using this.. I was actually thinking of making a program similar to this, but you did it way better than I could.
The main improvement I would make is to edit the sounds being used to have them play instantly, instead of at a slight delay. Currently, whenever I press a key, there is about a third-of-a-second delay until the sound plays. This is likely in the sound files themselves, and you could edit the empty space before them so the sound plays immediately when a key is pressed. In my opinion, this would make it more satisfying.
Thanks for making this!