Yes yes yes, you said the RPS coverage of Left 4 Dead has so far been the greatest games writing you've ever had the good fortune to read, but why haven't you been able to see an enormous selection of screenshots from the first two campaigns of the game? We heard your cries, and here they are. See below.
No Mercy is the level set around and then in a large hospital, and you'll likely have played its opening in the demo. Here's a clutch of grabs from all five levels, including a selection (toward the end) from Versus mode.
Blood Harvest is the most rural of the four campaigns, set in the woods, along a railway line, and finishing in a farmhouse defence. These shots are mostly from the first few sections (because they're the ones that looked best), and once again there's a few pics from our Versus battles thrown in there. The sepia tone pics only appear when you're dead while playing Infected, but they often look snazzy. But don't worry - you never play in sepia.