Pros: Nicely done spray, another good promo for L4D, this spray fits almost anywhere on the street levels, so it should be quite interesting.
Cons: I can't think of any cons for this spray.
Improvements: Perhaps later down the road you can do a Pro-military spray, something of the affect where a soldier is shooting a zombie with a sniper rifle, perhaps a "Boom Headshot" Spray.
Notes: Hopefully Mercy Hospital will be something useful instead of another run down old hospital where everyone's dead. I've been thinking alot about the third level and the next one after, I've been wondering if Mercy Hospital will have actual people there holding the line. Also if you do get the chance, make a No-Bombs Spray, I think the town is going to be nuked in the 5th level.