It's really difficult to explain the game because it's kind of like trying to explain Dwarf Fortress or EVE Online.
However with X4, it's a game that is seemingly the return of what made X3 great, and what most people find as the quintessential aspects of the X series. Rebirth that was released a few years ago was a disappointment as most people wanted a sequel to X3: Terran Conflict and Albion Prelude in terms of game design, and not a game akin to the design of the first, since most fans found that the series had its best features and design in X3, so Rebirth taking you back to owning only a single ship, with limited fleet and corporate/organisation building mechanics was a big departure.
They're niche space games since they've generally had a steep learning curve relative to other space games and games in general.
I am a big fan of the X series and been playing them since the first entry in 1999, X: Beyond the Frontier.
