Kill 3 enemies at once 10 different times (on any difficulty)
Killing 3 enemies at one time will require a grenade, Boom Shot, Hammer of Dawn, or possibly a well-aimed sniper shot. The easiest way to do this is to do the following:
Start the game's campaign on Casual. In the prison, when you reach the door that the locust start to cut down to get through, hide behind the barrier closest to the door. Right before they break through throw a grenade. Time it and position it so it kills all 3 of them. If it doesn't, let the ones who lived kill you. If it does, run outside and let those Locust kill you. If you try to reload the last checkpoint through the Pause Menu instead of getting killed, it won't count. Repeat this 9 times to get this achievement.
Please note that you cannot reload the checkpoint as the video shows. If you do, the kills will not count. Instead, run outside and let the other locust kill you.
Before the end of the first act, there's a door, which is smashed by the Locust. It's at the time, when Dom says: "They're cutting through the door, take cover! Take cover!" Just throw a grenade at the right time, when they're coming through and you've killed 3 enemies at once. Do this 10 times. It's very easy.
I tried it exactly 22 times, and realized that the exact time to throw the grenade is when the door touches the ground during the blast. Sometimes one survives because he was late or went fast. When I discovered that I was already in 14 attempts.
Heh... I was trying what #2 was saying but either my timing was off, or one of the three grubs would be late coming through the door. So I stood at the door (just outside of it's blast radius) and waited for them to blow it up.
Then i'd rush the door as soon as it was blown open and grenade tag the first one in line. Even if it killed me along with them, it counted. My achievement just popped on one of the times I was killed.
Did the kamikaze strat that #6 had and it worked wonders. Probably just over 3/4ths of the attempts were successful at killing all 3 grubs and the achievement did pop on the time I was killed. Much easier than the timing of the throw.
Glad my advice helped you out! Honestly, I had no idea it counted, but I was getting too damn frustrated chucking a frag only to have one of those grubs hesitate. Mainly was just screwing around when the achievement popped up and thought I should pass this info on :)
Another good way for this achievement is Act 3, when you need to walk over the rotten wood and there's lambent wretches under, just fall down n when there's enough wretches around you, use ur grenande. Note that the wretches will never stop coming if you stay down there.
tried #2's way, failed miserably. #6's idea was great, got it in no time. It even helped me get better at tagging. Thanks #6 it's getting frustrated and doing things for the wrong reason that we discover a new way.