The civs must have a strong cultural (and military) identity in the 500-1 BC time frame, besides other reasons, to be included in 0 A.D. part 1, Burzum. Part 2 will feature civs in the 1-500 AD time frame, Imperial Romans and Huns are included on the list. The Egyptians were initially not included because the Egyptian golden age was before this frame. But because of fans' requests, as well as from some within the team, the Ptolemies (the closest to Egyptians in our time frame) were included on the list, after the Mauryans' success as a crowd-sourced civ (special thanks here to lilstewie for his searches).