There are coding techniques that will reduce the "feel" of input lag, but I doubt they are using them. For example, they could render and transmit each screen larger than needed (IE add a bit of overscan). By pan & scanning in real time on the client you "may" be able to fool some players that there is less lag. You'd have to have sophistacted routines to tweak the scaling of the image, but it's the same sort of techniques used when created panoramic photos or correcting wide angle distortion so nothing complicated really. You could also zoom in & out of the image to create the impression of immediate feedback for W & S keys. A&D straffing would be a simple pan, parallax would go out the window but again, I'd say it could improve the feel.