The Portugal civilization would make better sense with the Pirates: the Golden Age of Piracy scenario, instead of the Zombie Defense game mode. Well "better sense": Portugal is not part of the 4 colonial powers since they didn't really set in the caribbean. I guess it is "better sense" in a sense it is a less "worse sense"?
Zombie came from the West African Vodun, a distrinct fom of the traditional African religion mostly in Benin, Togo (and part of Ghana and Nigeria). Due to the African diaspora in America, other countries like Cuba (Vodú), Dominica (Vudú) but mostly Haiti (Vodou) are praticing to some degree the same religion. And to some extinct: in Brazil (Vodum) and the USA (Voodoo).
It is quite a missed opportunity for the inclusion of Benin or Haiti. Before being exposed to some US-american pop-culture media, for me a Zombie was mostly an Undead servant (like a Civilization V's worker!) than a slow-moving never-ending horde of brain eating diseased people.