Kill an Enemy While Playing as an Alternate Character Costume Other Than Drake

Kill 30 Enemies with the Mk-NDI

Defeat 20 Enemies by Blind-Firing While in Cover (without aiming)

Kill 30 Enemies with the KAL-7

Hit 3 Enemies with Fish in the Market

Kill 30 Enemies with the G-MAL

Successfully Counter all of a Brute's Damage-Giving Attacks

Defeat 50 Enemies with Hand-to-Hand Combat

Kill 20 Enemies with Headshots

Obtain the Gastro Fork.

Complete Chapter 1 of Story Mode.

Enter trance 50 times.