The Perk system in Wolfenstein: The New Order allows you to customize BJ's abilities based on your playstyle. Perks are unlocked by performing specific actions repeatedly, such as getting a certain number of stealth takedowns, dual-wield kills, or grenade kills. There are four categories: Stealth, Tactical, Assault, and Demolition. Each category has several perks that enhance related abilities. For example, the 'Silent Shot' perk in Stealth reduces weapon noise, while 'Quick Reload' in Tactical speeds up reloads. Regularly check your Perk menu to see progress and plan your unlocks.
