Bodycount
42 Achievements
5-7h
PS3
Multiboom-doom
Kill 3 enemies at once with a single grenade
35.5%
How to unlock the Multiboom-doom achievement in Bodycount - Definitive Guide
Anxsighety
TrueAchievements
TrueAchievements
This will probably come from normal play for most people, but for those of you having trouble with it there is pretty much a guaranteed spot to unlock this. In Mission 8 you'll be back inside the target. While progressing through the level you will come to a part where it says to watch out for snipers. Directly after this when you hit your waypoint, it will tell you to eliminate the targets. 6+ enemies will all come running out of the door in front of you at the same time. All you need to do it double-tap RB to release a grenade, and it should kill at least three, if not all six of the enemies.
Hope this helps!
Hope this helps!
MEasy
The single player campaign is full of opportunities to kill up to 7 enemies with a single grenade. There is no single instance that is better than others. When you see 3 or more enemies close to each other, press 
and send them all to hell together.
This trophy can be done both on or offline; excluding private matches, it can also be obtained during co-op.