One of the most important Xbox One console exclusives, Titanfall is a first-person shooter based in a futuristic world of mechs. However, you'll play as both one of these giant metal monsters and a vulnerable little fleshy footsoldier. One is powerful, the other is fast and nimble thanks to a jetpack - able to double jump and take cover unlike a mech.
What's really interesting about Titanfall, though, is how it melds multi-player and single player gameplay. It's an online-only game, but incorporates story missions and single player-style events. It's one of the few games in our list that is not cross-platform, so Xbox One owners should take note of Titanfall.