Dead Space 2
50 Achievements
1,000
20-25h
The Nanny
Kill 30 Crawlers without detonating them
10
How to unlock the The Nanny achievement in Dead Space 2 - Definitive Guide
Here's a quick guide, that is simple. Use the Flamethrower. 'Nuff said.
I also wanted to add that killing the babies also helps you with the Necro Flambe achievement as well. So you are getting 2 birds with 1 stone.
The Flamethrower is a very underrated weapon, I even used it on my Zealot playthrough. If you full max out the damage you get a cool looking blue flame as well.
To kill them without detonating them, you can use the Plasma Cutter and shoot off their head. This will kill them in one shot, though can be tricky since they will be crawling towards you, and if your aim isn't true, they will explode and possibly harm you.
Alternatively, to make this trophy trivial. You can use the Force Gun (found later). One shot will kill them, and they will NEVER pop (Unless you use it's alt fire. Don't.) Depending on how well you do, you will get this trophy your first playthrough. Or, you may need to obtain it in NG+.
Crawlers are infants with an exploding sac on their back, which you will encounter first in the Elementary School in Chapter 6, 9 and 13. It is possible to obtain this in one playthrough, but you will need to attempt this everytime you come across Crawlers. You need to aim to sever their heads or legs off, and the Plasma Cutter's ALT attack (in horizontal position) is ideal for this, as well as the Force Gun and Flamethrower.
You will first encounter these creepy, baby necromorphs upon entering the "school" portion of Chapter 6. You haven't encountered the force gun schematic yet, so you will have to be careful when approaching these as you will only encounter approximately 40-45 of these in one playthrough. Use stasis on the group of them and then just shoot at their head to kill them. Using the plasma cutter, you can aim toward the bottom of their head that is closest to the ground. It will sever them without exploding and makes it pretty hard to accidentally miss. If you happen to detonate one, most likely killing numerous Crawlers, I recommend that you restart your checkpoint. After Chapter 7, use the Force Gun on Crawlers as it doesn't cause them to explode.
This is also cumulative across multiple games.