Kill 2 enemies with a single bullet in Single Player or Special Ops.

Acquire all remaining medals

Finish the game in Normal Mode

Defeat 20 enemies with gunfire by aiming while hanging

Defeat 20 enemies with the Pistole

Defeat 100 enemies with headshots

Find ten treasures

Defeat 30 enemies with Mk-NDI grenades

Defeat three enemies with one explosion

Defeat 20 enemies with hand-to-hand combat

Kill 1500 Helghast soldiers

Achieve 8 medals on predator challenges