Call of Juarez: The Cartel

The achievement is pretty straightforward. Simply complete every single level as Eddie Guerra to unlock this achievement. It can be done in either single player, or any form of co-operative.

Since you need to do a Hard Playthrough, get that out of the way (preferably in Co-op) and then just do a speed-run of the game with the two characters you missed to unlock their respective achievements as well.

If you want to make it easier, use the invincibility glitch. In a single player game, if you activate Concentration mode and then restart your checkpoint, when you restart you should be given a lot more health. This needs to be done at the start of every chapter/act if I remember correctly.