Zombie Apocalypse

As my fellow gamers have mentioned, a survivor is a lady in a blue suit with a blue cross above her head. She appears twice on each level. Whenever you hear her scream for help, locate her, touch her and fight off zombies until she is rescued by a chopper (that should take about 10 secs).

A few tips:

1. You'll have to solo it (or make a pact with your squad mates that they do not attempt rescuing) so that each survivor will be credited to you. You won't make it with the four initial lives, but don't worry, as:

2. You are allowed to lose all your lives and then continue, and the survivor count will not reset. So you'll probably have to do quite a bit of dying for this achievement.

3. But please do not quit the game entirely. If you quit out and then continue, you'll have to do it all over again. So, save all the 25 in one sitting.

4. Use your Teddy Bear to lure zombies away from the survivor. This will make rescuing much easier, and as soon as the survivor is picked up by a chopper, they drop down a new Teddy Bear for you (and you are allowed to carry only one at a time).

Hope that helps.

Since you can use unlimited continues in the game, just start the game from Day 1. Keep helping survivors until the achievement pops up. It took me several weeks to get it - at most I noticed you can help 2, maybe 3 every now and then, survivors a day. of course you can't always save all the survivors.

like Chotkiy said above, if you just want this achievement then it's wise to use your teddy bears since another one drops for you when they are saved. if you already have zombie bait, you get 100,000 points (good to go towards earning extra lives).

survivors cannot be harmed by your weapons, so feel free to chainsaw in circles or use a flamethrower all over the place, the survivor will survive!

As stated above this has to be done in one play through. You cannot for example, do the first level and then quit to the menu and go back and do that level in order to gain the achievement.

If one player gets all of the survivors you should have this by Level 15, as a few levels do not have any survivors.

My co-op partner and I found the easiest way to get this was by using all weapons and starting on level 1. Use the flamethrower or mini-gun and you should have no problems at all grinding through these early levels.