Right so after grinding out a good amount of long hours and zombie killing acquiring the zombie parts required for the zombie antivirus research quest, I was immediately gutted to see that I had to acquire more zombie parts as part of crafting the vaccine. Now I understand that some part of a zombie would be required, but 4 parts is too much (not including the quite rare antibiotics required now). It took me nearly 200 zombie kills to finally get my last zombie heart and after going through much grinding to only having to do more grinding for parts was soul destroying and has almost made me want to take a long break from the game. I thought by grinding out the research I would be able to efficiently able to make the zombie anti-virus, instead the require components considering the amount of more grinding to do for them is counter productive. I'd be better off going to a spawn location, killing myself and then grabbing my gear again.
My suggestion? To allow players to specifically target areas to cut when they need zombie parts, perhaps an expansive menu like the repair menu for vehicles. To balance this, make some of the parts have a much rarer chance of success. Example - High Success: Zombie Leg, Low Success: Zombie Brain