Break out of Abstergo.

Kill three enemies with one explosion five times

Kill five enemies in a row with a single punch, after softening them up with gunfire

Finish the game in Hard Mode

Kill 20 enemies melee-attacking from behind

Kill 50 enemies with the SAS - 12

Kill 30 enemies with the Dragon Sniper

Kill 20 enemies with the Wes - 44

Find the Strange Relic

Kill 10 enemies with grenades by aiming while hanging from a ledge

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

Finish the game in Easy Mode

Kill 20 enemies with Mk-NDI grenades