I found the level (Shore Leave) to be a pretty much non-stop affair, quite a bit different from Crysis which has lulls and downtimes between large set-piece battles. In Warhead, you're propelled from one encounter to another. The game doesn't quite have the over-the-top intensity of Call of Duty, but it will still keep you on your toes. That, and the sandbox environments will have you constantly thinking, as you can change tactics and approaches on the fly. If the rest of Warhead is like this, it should be good news to those who felt that some of Crysis' passages were too linear.
IGN: Pre-E3 2008: Crysis Warhead Hands-on