How to Earn 'Grenadier', 'Access Denied', and 'Cheap Shots' in Resistance 3

In this Achievement Hunter guide to unlocking PS3 trophies in Resistance 3, the guys walk us through how to unlock 'Grenadier', 'Access Denied', and 'Cheap Shots.' It may take a few tries to earn the Access Denied trophy because the shields are time based instead of damage based, but if you're in an area with enough enemies you can get it after a few attempts.