Pretty cool. I feel like the purple dudes need to follow your cursor with you or the gameplay feels like just trying to get all 4 purple dudes in your cursor and lock them in. loses the original gameplay of moving your cursor around.
I agree, I wanted the demo to be a self-contained experience which is why so many of the upgrades feel quite linear, and once you get the preacher's that's all you care about, but for the full game there will be more types of creatures and resources, the map will increase in size, and I'll also make sure the preachers stay a bit further away from each other :)