Obtain 12 000 points in the Kunlun Mountains mission in the Campaign
There are many opportunities to perform melee kills in this mission. Melee kills are as good as headshots, earning 25 bonus points per kill. You will need five Shank (melee) kills for the Shawshank trophy, which is easily achieved by running up to the first five enemies and pressing . You should be able to get some multi-kills after freeing Irish from his cell. Several enemies will rush down a narrow corridor and well-thrown grenades with well-timed shooting should help you rack up bonus points. You can headshot your way through the next area and then you will gain access to claymore explosives. Plant them, if you wish, and hopefully this will result in some multi-kills when enemies are deployed from a helicopter.

You will happen upon more melee chances when you go outside into the snow. The first several enemies can be Shanked without being detected. You can then grab the RPG from the gadget stash and destroy the tank. Concentrating on headshots for the remainder of this area should prove sufficient. Use cover often, because some enemies here will have grenade launchers that deal strong damage.

Following the previous area, you descend down an elevator and into a narrow hallway where a few small groups of enemies will rush you. I used this opportunity to perform several multi-kills with grenades and assault rifle fire. You can restart the checkpoint and begin right in front of the hallway until you are satisfied with your performance.

Lastly, you will go outside onto the scaffolds of the dam. By now you should be very close to your points goal, if you have not already surpassed it. If you still need more points, you will likely earn them from scoring headshots on the enemies that appear on the scaffolds.

Please see Above and beyond the call for point-scoring tips.