As does XCOM Declassified.
2K confirms "reductions", won't say how many.
Hangar 6 prequel expansion is Xbox exclusive.
UPDATE: Oh it's just timed exclusivity, 2K confirms.
From the people who made BioShock 2.
"The time is right to deliver a new experience within the world of XCOM."
Leaked screens show new look for delayed FPS.