XCOM 2 is a sequel to the 2012 Game of the Year XCOM: Enemy Unknown
. Enemy Unknown brought life back to the Tactical RPG genre and XCOM 2 did nothing short of raising the bar even higher. XCOM was, before 2012, a series nobody had heard from in years. Firaxis, the company behind the Civilization series, got the rights to continue the series. XCOM: Enemy Unknown was actually announced after news of another nontraditional XCOM game (later revealed to be The Bureau: XCOM Declassified) that it proceeded to stomp in terms of reception, making the Enemy Unknown series the mainstay.
XCOM 2 takes place in an alternate reality to XCOM: Enemy Unknown, but shares more connections than one would initially expect. Without revealing anything unannounced, the two realities do share a Central Officer named John Bradford. The story of this alternate reality is that XCOM lost the way a few months into the alien invasion and they were mostly destroyed. Bradford and a few of the supporting characters survived the fallout, but Earth was soon turned over to the aliens in a “peace treaty” that obviously turns out to be a farce.
The biggest difference beside story however is the tactical approach. XCOM is no longer a defense force for planet Earth. Emerging from the shadows after 20 years, the XCOM project returns as an offensive guerilla-style operation attempting to tactfully strike back at the enemy to retake the planet. This displays itself in the gameplay, the tone, and even the graphics. XCOM was never a game that needed story to be good, but Firaxis weaves a perfect retaliation story into a complex, thinking-man’s game.