Banana Bomb
Complete Shotgun Challenge 3.

Bridge Kit
In the Beefcake Breakfast, get the crate located on a rooftop.

Earthquake Weapon
Complete Jetpack Challenge 3.

Mad Cows
Complete Shotgun Challenge 3 with all golds.

Nuclear Bomb
Complete Deathmatch Challenge 10 with all golds.

Super Sheep
Complete Sheep Challenge 3