This is just an evolution of the stuff they've been doing in the other games. It's taking the core gameplay mechanics they setup singularly and in smaller scale during "regular" gameplay, and put them together in an expertly staged and escalating setpiece sequence. You have third person cover shooter and traversal. You have jeep driving (evolution of the train level from Uncharted 2, and the horse riding from Uncharted 3, where now you are in control and have multiple paths). You add the use of the rope. You climb up the rope and can shoot from the rope. You have traversal from vehicle to vehicle (this is an evolution of the
vehicle sequences towards the end of Uncharted 2). You have more jeep driving. All core gameplay mechanics.
Then you jump on the motorcycle and this is really the only part of the entire demo where you have little control, just shooting, but this represents an astronomical evolution of this sequence from Uncharted 2, which took place in one alley and lasted about 30 seconds:
Looked incredible to me.