Power/Pack-a-punch - First you will need to turn on the power and pack-a-punch
Klaus - Now you need to build Klaus
Blacklight - You will now need to get the blacklight
Free CRBR-S - You now need to get the CRBR-S.
Headgear - Go to spawn (Apartment Rooftop) and use the CRBR-S to shoot the radio tower on top and it should fall and drop a part for you to grab. Now repel down and go into the Electronics Store and shoot the three radios and one of them will drop the part. Go down to the Ghost Station and shoot the box with a green light above the ammo box. Now put the headgear on Klaus.
Upgarde - Now do the steps to upgrade Klaus.
Hidden Lab - Make sure you have the laser variant of the CRBR-S . Go to the Sewer Access and call Klaus to the brick wall next to the zombie window in front of the stairs. Klaus will punch it open and you will need to shoot it with the laser CRBR-S. Wait a round until the room no longer has red barriers around some of the items. Now go to the middle and wait for three canisters to rise and pick them up. Now go to the box on the wall that had a red barrier and shoot it with the CRBR-S and pick up the part that comes out.
Essence Harvester - These will look like small blue machines. You will need to find 3 of these. Once you find one interact with it, throw down a tempest trap and kill the three tempests close to the harvester. When it glows purple to the canister and take it back into the the place where you took them in the hidden lab. The first spawn is in the Sewer Access. The second is in the Ghost Station across from Mule Kick. The third is outside of the bar where Juggernog is. The fourth is next to a dumpster in the Alley. The fifth one is on the Korber Rooftop near Speed Cola. The sixth can be found at the back of the Destroyed Penthouse. The seventh spawn is outside the white shack in the West Berlin Street.
Keycard - Activate Klaus. Go over to the Switch Control Room and interact with the switch between the two chairs at the control panel. Now place Klaus in the center of the tracks farthest from Mule Kick. Now a subway will stop and you need to get in it and pick up the warhead and keycard under a zombies hand next to the warhead. Make sure that you did pick up the key since there will be intel there too. Now place the warhead where all of the purple canisters are. Then use the keycard on a computer in the Safe House.
Uranium - Once you are ready, use the satellite on the computer. Now go back up to the pack-a-punch area and kill all the zombies and mini bosses that spawn. Once you kill them they will drop uranium. You will only have 5 minutes to do this next step and if you don't then the game will end. Pick up the uranium and build it at the workbench in the military tent in the East Berlin Street. Now pick the device. Zipline up the spawn building and then zipline over to the hotel and place the device on the zipline that is through the KORBER sign. Now pick up the other piece of uranium and build it and take it up to spawn. Now use the other zipline and place the device on the opposite side of the zipline with the device. Now go back down to the street and pick up the rock that is under the zipline. Place that where the purple canisters and warhead is at. Now you will need to do this uranium process one more time. Once you have the second rock take it back down there and drop it next to the purple canisters. Get everything that you need to be ready for the boss fight. Pick the rock up and place it in the purple canisters.
Boss Fight - The boss, Valentina has 3 different attacks. The first one is yellow spikes and you just have to run away from them. But if you do get hit, she will only attack the armor until it breaks. The second attack is healing, which is when she has a ring of zombies around her and all you have to do is kill those zombies. Her final attack is when your screen will start shaking and start turning blue. All you have to do is hide behind something an get out of site. Once she is dead you need to escort Klaus into the reactor by killing all the zombies that come by. Once he reaches the end a cutscene will start.