On 3 separate occasions, lure other players onto a wrong answer, then switch to the correct answer with less than 3 seconds left on the clock.

Finish the game in Normal Mode

Defeat 20 enemies with a single punch, after softening them up with gunfire

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

Defeat 50 enemies with stealth attacks

Complete all Day 1 challenges at gold level

Defeat 20 enemies with the Pistole

Defeat 70 enemies with the M4

Find 40 treasures

Defeat 30 enemies with Mk-NDI grenades

Defeat 50 enemies with hand-to-hand combat

Defeat 20 enemies with headshots

Defeat 20 enemies with hand-to-hand combat