There are seven Blueprint Challenges in total, and they’ll unlock upon meeting Patton for the first time in Venice Beach. Completing each one will reward you with a weapon upgrade blueprint, so they’re well worth doing. They are as follows:

• Perform 100 Heavy attacks for the Contagious Blueprint
• Inflict bleeding status 50 times for the Infectious Blueprint
• Inflict ignite 50 times for the Infernal Combustion Blueprint
• Slay 100 zombies with melee weapons for the Leechblade Blueprint
• Knock down zombies 100 times for the Shockwave Blueprint
• Inflict the ‘electrified’ status effect on zombies 50 times for the Static Charge Blueprint
• Collect 200 zombie parts for the Vampire Blueprint

While most are relatively straightforward, if you’re struggling for zombie parts for the Vampire Blueprint, you can find an abundance of zombie parts in the Medical Disposal Waste bins at the CDC Center, near The Pier in Santa Monica. These also respawn zombie parts when you leave.