Don't get me wrong, the levels are great. Alot of fun and very detailed. However, I think the game could really benefit from some larger, more open levels in the future. Nothing huge, but take the first New York chapter for instance. When you exit the mall you have to find the subway. You walk out and just around the corner, there it is.
Imagine if you had to look around a block or two before finding it? It would open up the level immensely, giving more options for exploring.
I don't know if it's even possible, without tanking the frame-rate, but it would be cool regardless.