The Medic class in Killzone 3 appears to be one of the most underrated classes in the game, as most of the community plays as the Marksman and Infiltration classes. However, I feel the Medic class is vital for a team that plans on actually winning the match.
The video above gives a general overview of what the Medic class does and how I think an effective Medic should play. Hopefully, the video will also give some players an incentive to try out the class and see that playing on the defensive isn't as bad as one might think.
