Simple. It takes a bit time to code, but:
Have the original freeware game as a "bonus" mode for the commercial version, for if you want to take a break from your kingdom management, graphical beauty and fancy colors, and long to the simplicity of the freeware version without having to quit the game and load up the freeware version itself.
This version includes all alpha features and game balance, as pixelated graphics.
Maybe a few little changes; e.g. if you want to change the layout of the mouse cursor later in the beta, then keep that mouse in the classic mode. Just for the sake of uniformity.
Other than that, what do you like about this idea?