Play challenge mode to unlock additional weapons and add-ons. You can also get your score on the leaderboards.

Unlockable	How to unlock
Be More Objective 1	Lobster Grenade Launcher / Ritchie Revolver / Duct-Taped Magazines.
Be More Objective 2	Bulpdaun Submachine Gun / Speed Slings / Speed holsters.
Be More Objective 3	Score on Leaderboard.
Escort Duty 1	High Powered Scopes / Red Dot Sights / Muzzle Brakes.
Escort Duty 2	EZ-Nade Auto Grenade Launcher / Drum Magazines.
Escort Duty 3	Score on Leaderboard.
Parkour This 1	Barnett Light Rifle / Front Grips / Rapid Fire.
Parkour This 2	Belgo Machine Pistol / Silencers.
Parkour This 3	Score on Leaderboard.
Tower Defense 1	FRKN-3K Assault Rifle / Underslung Grenade Launcher / Adjusted Iron Sights.
Tower Defense 2	Gotlung Minigun / High-Capacity Magazines.
Tower Defense 3	Score on Leaderboard.