The Darkness II

This achievement took me forever! Hopefully this video will help some people out.

Make sure you reload between sections and do it on easy! It will make your day much better.

Got it on my second try. As stated above, do it on easy and reload your gun during the brief breaks in the action. They almost always occur while moving from one mini hot zone to the next. Auto lock onto each target hit them once and move on. Even if you miss 2 or 3 targets you can still get this achievement with relative ease.

If you're having trouble hitting anything during the dual wielding segment just make sure you put the cross hairs over them and squeeze both triggers simultaneously. Pace your shots to keep the reticule a manageable size in the same manner you would if you were shooting a single gun from the hip. This will maximize your chance of getting a hit (you only need one hit to kill on easy). Good luck!

Once again achievementhunter.com has your back on this achievement.
Michael and Mike show you how to get the "One Man Army" achievement in The Darkness II.
(FYI:the fat woman does not count and playing on easy makes everyone go down in one shot)
(before you "thumbs down" my solution let me know what I can do to make it better)
(all credit belongs to Micheal from achievement hunter for this video)

what the top post say is good. but to realy make this easy is to take a piece of tape and put it where the cross aim is on your tv. I like many others spent some time with this. I put the tape on the tv, and the very first time i got it with no problem. my problem was i could not see the cross to hit them. good luck