The Civilization franchise as a whole is probably the first thing which comes to mind when thinking about the 4x game genre. 4x games are about eXploration, eXpansion, eXploitation, and eXtermination. In Civilization VI you lead a civilization from the dawn of civilization (3000 BCE) to the information era while researching technologies, building wonders, developping your culture, creating great works of art, music and writing, conquering your neighbours, founding religions and all this on a hexagon tiled world map which might or might not look like a real world place with or without a civ which existed at this epoch. Never heard of the Industrial era Aztec empire in all his glory? Me neither but that what makes Civilization as a franchise so interesting.

But what differentiates Civilization VI from it's predecessors? Well, first of all there's the district system. Basically you don't build your libraries in your cities but in districts which are placed on the world map. There's an adjacency system which gives bonus for well-placed districts (next to mountains or other districts). Also wonders have to be build on the world map and sometimes have to fulfill certain conditions like being next to a certain district and/or on a certain terrain feature which makes it harder to mass wonders which is in my opinion a nice change. Also wonders were nerfed compared to Civ V which don't make them anymore a necessity but more nice-to-have which is welcome too.

Also another big change compared to Civilization V is the card system which makes for a more fluid and interesting gameplay. Do you want to focus on expansion or more on wonder building? Now you have to decide those things by either putting a expansion focused card or wonder building card in your governement which starts with very few card slots to others with bigger flexibility. Also the choices of a government early games affects you also in the late game because former governments grant you a legacy bonus.

The base game also includes religion and the new religion victory. Convert half the cities of all enemy civs to the religion you founded and you win the game (no religious victory for Kongo though). Alternative ways of winning the game are the science victory , cultural victory, domination victory and the score victory with their own unique flavour though spoiler score victory is really boring

If you buy the expansions, you'll be granted the loyalty system, the golden-dark age system, environmental effects, world congress, new 21st century techs and policies, and the diplomatic victory as most notable features as well as plenty other civs.

All in all I would say it's a worthy investment in money and I'm pretty excited to see what's up for the future of Civ VI

Be warned though that you'll might check the ingame time and wonder why you're still playing at 2AM.