I just saw that something called Unreal Engine (a game design software) has stopped being commercially sold. Users can download it free of charge after registering with the website, and for commercial development the Unreal Engine copyright owner takes 10% of all royalties over $3,000 earned by using Unreal Engine. Pretty silly terms for someone interested in commercial game development, but sounds acceptable for a hobbyist.
So does anyone know anything about Unreal Engine? Is it any good?