I found this was easier to do solo, after trying several times with multiple co-op partners. I would find that I was getting kills stolen, panzer soldats took a lot more to kill and at higher rounds spawned several at a time, I would be lacking points for perks/weapons sometimes too, and most annoyingly team mates activating a generator whilst I was on the other side of the map.
The challenges are:
Capture 6 generators
Spend 30,000 points
115 Headshots (On normal zombies)
Fill all chests
I got the achievement on wave 16, had a PaP'ed STG-44, PWD, and SCAR.
The idea is to maximise your points early on so you can get the perks you want as soon as you can. For me those were Juggernog, Quick revive and Speed cola (I also got lucky with a Mule kick for extra fire power).
You need to play whilst focusing on the challenges (Obviously...) That means, aim for the head whenever possible to get the 115 headshots, spending 30,000 points, (Dont waste your points...) By opening up areas to the generators, buying weapons and ammo and pack-a-punching you shouldnt struggle to spend your points. That being said dont waste it, save as much as you can for pack-a-punching/perks.
The way which I suggest to do this is as follows;
From wave 1 try to maximise your points (5 pistol shots to the body followed by a knife) and activate the first generator as soon as you can. (Side note I also bought an MK14 off of the wall at spawn for headshots). Also buy a quick revive before you move out of this area.
Grab a shovel and work your way around to the second generator digging up all the spots you can as they can yeild blood money, zombie blood (Extremely useful for activating the generators) double points and weapons.
Activate generator 2, after that was done, I bought the MP-40 (Great for headshots, and several spots to buy ammo [Shelter, front of excavation site, and behind Juggernog]) from inside of the shelter and continued to earn 2500 points before moving on. This is because you are at an open area and shouldnt get too over-run by zombies.
Run on up to generator 3 (You should be on wave 4-5 by now) and activate it when you can (Beware of the area to side of the generator is in the path of one of the giant robots).
I chose to stay here for a round or two to buy speed cola, and get enough points to open the next door in the area leading to no-mans land.
After entering no-mans land, head left at the excavation site, towards generator 4, again activate it as soon as you can. Your going to want to buy a Juggernog as soon as you can as the Panzer Soldat will be coming soon (for me he spawned at wave 7 or 8, AIM FOR THE HEAD, a few well aimed shots will take him down piece of cake). Now head over to the other side of the excavation site to generator 5.
Activate generator five, once that is done run over to the excavation site and head on over to the church where you'll find the sixth and final generator. (This one in my opinion coupled with generator 5 is the hardest as they are next to zombie spawns and are in a small area).
I advise buying the STG-44 from out of the church, as I found it possibly the most effective way of dealing with those pesky zombies. After the sixth generator is done you will have completed your first (possibly second challenge if you've managed to get the 115 headshots) You will be rewarded with a max ammo if you claim your reward for capturing all generators and Pack-a-Punched weapon for completing the Headshots.
From here I back-tracked and started to work on the chests, the first one being nearest the church, as it was close enough for me to run back to the church to get ammo for the STG if needed. After that I had enough to PaP (Pack-a-Punch) the STG-44. I headed on over to the chest behind Juggernog next. This is when the next Panzer spawned, at wave 13 if my memory serves me correct. However against the STG he didn't stand up too well.
Moving on to the next chest at the bottom of the stairs near the excavation site, beware though, there are several routes the zombies can come from so dont let yourself get trapped between a wall and a zombie.
After filling that, you'll almost be there! Fill the final chest up by the fifth generator, and the achievement should be yours! If you need to spend more points, PaP another weapon or spam buying ammo for a weapon (it costs 4500 to wall buy ammo for a PaP weapon)
- Always aim for the head. Always...
- Perks are your bestfriend, Juggernog is essential to your survial and Quick revive incase you get downed.
- Dont get side-tracked with the random box/perk machine, staff parts, etc.
- Play with the challenges in mind.
- Dig as much as you can.
- Avoid nukes, unless you need to escape from an army of zombies.
- PLAY ON EASY