Pros:

+ Creative level design
+ Lots of ammo and pills
+ Nicely decorated maps
+ Plenty of oxygen tanks, propane tanks, and gas cans

Cons:

- Not enough throwables
- Strange spawn points for infected
- Short maps
- Way too many tier 2 weapons scattered throughout maps
- Finale needs work; see conclusion
- Perhaps too many pills
- Not much to explore

Conclusion:

Thanks for making a map for L4D1, there truly aren't enough. Maybe work on making longer levels and this campaign would be great. I was playing on single player and Bill got stuck at one of the ammo piles on Map 4. The finale was very easy. Also, when the rescue train arrived, I had to run after it. Then it said all 4 of us survived even though we weren't on train. When the credits starting rolling, the game was still playing. I could hear everyone still shooting and more infected spawning. Needs work.