I absolutely love your rendition! It's beautiful, the choices of editing colors with an XML file is great and everything's labeled for easy changing. I did a let's play on your game to showcase not only the game but a test bug that I came across.
Bug: When starting game, the choices for Size and Difficulty are pre-selected to Small and Medium - the other buttons work on hover / can click but do not select, the choices stay at Small and Medium on the GUI (showcased in video bellow). Hope this helped and I can't wait for your finished versions!