Kill 20 enemies melee-attacking from behind

Finish the game in Hard Mode

Find 30 treasures

Kill 50 enemies with the Moss - 12

Kill 20 enemies with the Wes - 44

Finish the game in Easy Mode

Kill 20 enemies by shooting from the hip (without aiming with the L1 button)

Find 20 treasures

Kill five enemies in a row with headshots

Kill 30 enemies with the MP40

Kill 50 enemies with the M4

Kill 50 enemies with the Micro - 9mm

Kill 100 enemies with headshots