GAC Helmet
Difficulty=EASY
Unlock: Get 30 headshots in any level on OFFICER difficulty or higher

GAC Armor
Difficulty=AVERAGE
Unlock: Complete the game on OFFICER difficulty

Logo T-Shirt
Difficulty=AVERAGE
Unlock: Complete the Protect the Innocent Achievement

GCPD T-Shirt
Difficulty=AVERAGE
Unlock: Complete any level (excluding the Prologue) without firing a shot

Jack and Shadow T-shirt
Difficulty=AVERAGE
Unlock: Combine Jack and Shadow to kill 20 enemies in any level on OFFICER or greater difficulty