Choices have consequences, but most games tend to forget it. Barring the cause-and-effect of trigger, bullet and hitbox or grenade and explosion, only the best games force us to genuinely experience the ramifications of our actions - and even some of the shining beacons of our industry sometimes...
Staggeringly deep strategy made accessible and brutally visceral; Cerebral non-linear gameplay predicated on choice; Open-ended; replayable and massive in scope; The freedom to make your own mistakes and luck
Some recycled maps; More exotic and esoteric weapons/research projects would have been nice; Foes can move to cover on your turn (annoying; though not unfair