Call of Juarez

Just to clarify what you might have heard elsewhere about being the host to get this achievement.

I boosted with five people and got all other online achievements, approx 80-90 kills with one host. (not me)

Two people left leaving three to boost this achievement. The host went first (because that is what we thought) and got the achievement. I then went next and killed just over 200 more times and got the achievement. Just to be sure the third person did the same, proving that you do not necessarily have to be the host.

I recommend boosting for this, I did and got it done in a little over 2 hours with 2 other people helping.

We did a Player Deathmatch game on Twilight level and had the person getting the kills stay at one point in the level where you have a clear view down two sides of the street. The other players (getting killed) will run into the street and the shooter (going for achievement) will hopefully have a sniper rifle and can kill from far out. This strategy can be improved by climbing up a roof, getting more view for better distance shots.

Just as a more recent solution for anyone still going for this =]

Any kills count, you do not need to be the host for the kills to count, I was the host in a session and everyone gained their achievement!

Any kills gained in a 'ranked match' where the text saying waiting for players to join game text is flashing do not count toward this achievement!

And finally, you do not need to get all of the kills in one game, and also kills count even if you quit out or disconnect from the game, I got all of my kills through a few games in different sessions, and unlocked the achievement after getting 128 kills in my last match!

Good Luck!