Perform 5 "Screw Top" glory kills on The Possessed (attack lower right leg or head from behind).
Interact with 2 Rune Trial Stones.
Hide and Seek
Find 2 Collectibles.
Meet with Samuel Hayden in his office
Leave once you arrive at the station and go upstairs. In the first toilet on the left you will find additional armor. A group of demons will attack you soon after. Use the encountered Possessed to complete the challenge. Simply stun the beast with a melee attack and then perform a Glory Kill while standing behind the creature and aiming at his right leg.
Go forward until you reach a room with a panel. Use the panel to unlock further passage. Next to the computer you can take valuable Argent Cell.
After leaving the room you will bypass a door glowing in red. Behind it you will find Automap and Elite Guard. In order to get there you must go back to the toilet (the one without armor), stand on one of the sinks and turn around. You should notice a tunnel entrance - it will lead you to the previously mentioned secrets. Further path leads behind the door which you opened with the computer. Go forward and examine the place under the stairs. You will find ammunition - it will prove to be useful during the battle with the demons which will happen very soon.
Once the battle ends, use another panel and pick up the Data Log lying next to it.
Slightly further you will see a Gore Nest which you must destroy. Once you do it, hordes of demons will start appearing. After defeating two Mancubuses you should pick up the Berserk lying below. It will allow you to quickly get rid of remaining demons. Further path leads up to the office of the boss of the corporation.
After hearing the man you should pick up the documents lying around and then go to the elevator at the end of the corridor.
Get to the Weapon Research Division
Once below, pick up the Data Log. Turn to the right and under the wall you will find another Elite Guard.
Slightly further there will be a sluice which you must open by using the nearby panel. You will get outside where you must destroy the second Gore Nest. The Haste power-up lying on the right will be useful against the demons.
Use the computer marked by the radar once the battle ends. Before you go further to the mission objective, first walk through the sluice ahead. Behind it there is a Rune Trial hidden: Blood Fueled. During it you must kill all enemies in limited time. Additionally, you can move only for a few seconds after each kill. In order to complete this challenge you must run forward after each kill. When you notice a new enemy, shoot him with machine gun. For completing the trial you will receive a rune that will make you move faster after each Glory Kill.
Check the right corner of the room once you complete the challenge. Behind the chest you will find a game machine. You can play it, but there is no special reward for it. Now you can get outside through the sluice and then go to the left.
First jump on the first platform and then turn around. Below on the right you will notice a pipe. You must get to it - it will lead you to Argent Cell.
Jump to the edge on the other side after collecting it.
Stick to the left side and climb up. You will get to a cave with hidden collectible (Phobosguy).
Stand at the exit from the tunnel and look left. Behind the gate you will notice a lever.
In order to use it you must climb to the top of the rock standing in the middle of the location (you will find armor there). Then you must jump using the double jump.
The lever will open a Classic Map located near the Gore Nest you recently destroyed.
Further path leads to the tunnel marked on the radar. In order to get there you must wait for the hatch to be lowered. Once it happens, land on the hatch.
By going ahead you will reach the place from which you can get one floor higher. First jump on the higher ground at the wall with number 1. From there you should jump to the nearby metal platform.
You will have a hole above your head. You can climb through it.
Go forward and press the button on your way. It will activate a fan. Don't jump to the shaft yet - instead of that, go to the other side of the complex.
There you will find an activated fan which you must turn off. This will unlock a passage down where a Combat Support Drone is waiting.
Go back to the previously activated fan after selecting upgrade. Jump on it. The air current will throw you to the corridor above. In the room on the left you will find an Elite Guard. Search it and then go ahead.
Get to the Lazarus elevator
In the room behind the door you will fight a group of demons. Thoroughly search all nearby rooms after defeating them. In Prototype Lab 2 you will find Data Log.
Another one will be located in the Server Room.
Go to the Prototype Lab 01 after you collect them. Climb to the shaft on the right. You can jump towards the machine in the middle. The tunnel will lead you to a collectible (Pinkguy).
Now you can move to Security Room and pick up the corpse that is lying there. You will need it to open the door leading to BFG Prime Lab. The room can be found in the middle of the location.
Walk to the other side and climb on the elevation in the middle. Then wait a bit and jump on one of the platforms that appear at the walls. You will avoid security lasers by doing that.
When a big moving laser ring appears, you must wait for it to move up. Once that happens, destroy the four red brakes under it. This will cause the ring to fall and destroy the lasers below. You will be able to jump down and collect the BFG-9000.
It is a very powerful weapon which has just as limited ammunition as Chainsaw. You pull it out with a separate button and you shoot it like any other weapon. It creates powerful energy charge which hits all nearby targets. Test it on the demon army waiting below.
Use the panel in the middle once you get rid of all enemies. Then walk through the door on the right. There will be a narrow tunnel on the left, it will guide you to the Rune Trial - Intimacy is Best. In this challenge you must perform 8 Glory Kills in specific time. In order to complete it quickly, you must shoot each Imp with a special pistol bullet charged slightly less than to the half. This is the quickest way to stun the demon and perform an execution on him. The rune received as reward will speed up the enemy stunning, allowing you to use Glory Kills faster.
Now go back to the room with the panel you used before and this time go straight. Behind the big gate you will notice an army of demons. By blowing up the Possessed Engineer you should kill most creatures. Soon after that two Pinkies will attack.
In the room slightly further you must destroy a Gore Nest. Before you do it, thoroughly examine the room and item locations. At the top you will find Quad Damage power-up and BFG ammunition. Another ammunition pack is on the lower floor of the area. During the incoming battle you will also use the two pairs of teleports. They will move you between levels.
Once you destroy the Gore Nest, hordes of demons will start appearing. Use BFG and the power-up only on very strong enemies like Summoner and Mancubus. You should keep two BFG bullets for the second battle that will start after you use the panel next to the elevator. Two Barons will attack you then. Stand on the platform in the middle after the death of the last opponent and finish the level.