Complex sentence: Knights' Kingdom is a construction simulation video game for Microsoft Windows; it uses virtual Lego pieces to build a medieval kingdom and then use the kingdom in a battle against the character Cedric the Bull.
Split into simpler sentences: Knights' Kingdom is a construction simulation video game for Microsoft Windows. It allows players to use virtual Lego pieces, first to build a medieval kingdom, and then to use the kingdom in a battle against the character Cedric the Bull.