The straight dope on X-Com:
X-Com 2 is Terror from the Deep and was my favorite of the series.
Released by Microprose in 1995.
Sorry, but that one wasn't called XCOM 2. It was XCOM: Terror From the Deep.
I played the original, Deep, and Apocalypse, then the series went dark. I re-played the original in Windows XP with an emulator, but they never got the mouse drivers right. I played it about two years ago under Win7 with DosBox and it was pristine. But not as much fun as I remembered.
The current re-imaginings are far better games, both in graphics and sound, but also IMO certain design elements. You only have one base, but it is highly configurable. You don't have to fiddle with ammo clips anymore. And whole new pieces have been added, like mechs and new psychic upgrades.
I've been watching the newest one which launched about 2-3 weeks ago., It's still fully priced on Steam at $60. I'm still on Fallout 4, so there's no hurry. But once the new XCOM comes down, maybe this summer, I'll be playing it.