Possibly considered the father of all modern grid-turn based games, Enemy Unknown does feel a bit overshadowed by its successor in gameplay, balance, presentation, music, story, characterization and depth. Why play EU when you could be playing XCOM 2?

Honestly no idea, it's still fun and addicting, but it's not as polished as its sequel. Still recommended to see how an old IP got the reboot of its lifetime and to mow down some aliens, which is always funny until you get RNG screwed.