Yea they are definitely bigger,considerably.Game structure is made that way that in every new mission/chapter you get the info/story to what to do,its completely linear and you go through that.It is not long though,it depends on mission.
When they are finished talking you generally find yourself going to marked point,through streets you find yourself in quite big battlegrounds doing what ever the hell you want.Vertical gameplay is great as there is alot of buildings,passages,trucks,random objects that you can climb on and use tactical advantage and thinking how you are going to play.Its full of variety and its a game with lots of re-playability,