Get to the point in the first level in original mode, where the boy runs out the door with the Johnnys chasing him. After that, there are Davids that jump down from the bridge. Use a grenade (only) to blow open the door behind the David to the left. A grandmother will come out and give you a Bullet Blow, Grenade and other items (depending on how many times original mode has been completed).
In the beginning of the game after the women tells you to save the man, there will be a bucket behind him. Shoot the bucket and a Credit +2 will be sitting in the well.
Prelude: Different pathway civilian
The first woman civilian you see is being chased by a zombie. Save her, and she will tell you to save the man civilian, who will get attacked by three zombies. If you succeed, he will lead you in a different direction -- not a significantly different pathway, but it cuts through another pathway where a Max zombie will appear. If you take the different path, he will not appear.