Note: The numbers must not have been played with previously for trick to work.
For acid-spitting zombies, let the zombies get pretty close, then fire three steady shots with your Beretta. This will save you a lot of ammo.
To kill spiders quick, here's what to do. If you're Jill, arm the Bazooka with Flame rounds. Then when you encounter a spider let it get pretty close (or if you like, when it's ready to bite you), than fire! This works only agaist medium-sized spiders. You can try the Acid rounds, but it might take a shot or two more. For Chris, if you can pick up the flamethrower, use it agaist the huge spider. Just fire until it's dead.
"There is an outfit that fits you perfectly, do you want to put it on?"
Click "Yes" and your characters' clothing will change.
An easy way to remember is 1+2=3, 3+4=7, 4+2=6, 6+7=13, 13+3=16 (Water=1.)