When you gain control of William "B.J." Blazkowicz, head toward the back of the plane, turning left once you go through the first door. There's a cabinet there with pliers and baling wire. Grab them, then make your way to the back of the plane, crouching and heading for the fuel line compartment. Once you've taken care of the fuel line, head back the way you came, taking a right when you reach the cabinet where the tools were kept. Head down to the cargo bay, using your Knife to cut the straps on everything you see before returning to the cockpit.
Tip: Throughout this game you will find various types of boxes. Breaking them open with your Knife will often yield rewards such as weapons, health and armor.
The man who's been giving you orders, Fergus Reid, now tasks you with taking control of the turret that sits at the front of the plane. Do as he asks and start engaging enemy planes, taking out as many as you can before Fergus pulls you out.
Your next task is quite simple. Retract the radar by pulling the lever located just above the co-pilot seat on the right side of the plane. When that's done, open the plane's door and watch as Fergus jumps over to the adjacent aircraft. Once he's safely onboard, it’s your turn. Sprint and jump to the wing, then climb in and meet up with your new buddy, Probst Wyatt.
After helping to calm down Probst, you'll find yourself in the cockpit of a crashed plane. Grab the radio from the co-pilot's seat before breaking the box that leads to the rear of the aircraft. Once you're face to face with what Fergus described as a "Hell-Beast", sprint forward and slide as instructed at the top right of the screen. Don't try to fight the robot, there's no way to kill it just yet.
Hop in the water and swim in the only direction you can. When you exit the plane, notice a line with lights along the ocean's floor. Just swim along that line and it will take you your destination. Take control of the turret and gun down the two robots in the middle of the battlefield, then hop out to meet up with Fergus and Probst.
When you regain control of Blazkowicz, sprint straight ahead, through the trench and drop down when you can't go any further. Use your new weapon, the Submachine Gun, to take out the two Nazi's to your right. Head to the left, making sure to pick up any weapons, ammo, health and armor that you find. This next room should contain Hand Grenades and some health pickups. With the room looted, toss one of the Hand Grenades at the turret to complete your objective, then drop through the floor and follow the instructions on-screen to lean under the door and take out the guard. Make sure to pick up the Assault Rifle 1946 off his body before you move on.
Head left from the dead guard and start taking out opposition as you go. Keep moving until you see a set of stairs. Head up the stairs, take out the guards in the adjacent room and then keep moving through the building. When you exit, climb up the rocks to find yourself above the trench you were just in.
There should be a giant machine of death in front of you. Just ignore it and drop back into the trench. If you head right, you'll see the stairs you just went up a moment ago. Go straight and prepare to meet a Kampfhund, or as we like to call it, a big scary dog with armor. Use your melee to take it down, let your heart rate level out and then continue on your way. Stick to the trench and dispatch any bad guys that you come across.
Once you reach the end of the trench, crouch down and follow the directions on your screen to sneak up and take down the officer, then do the same with the soldier firing out of the nest. Make sure you loot the room and you should find a Handgun 1946 laying around. In fact, looting rooms should be part of your routine after you clear every area.
Your next task in the longest prologue of all time is to take out the Commander. He's just ahead of you, standing in the middle of three or four soldiers. You can tell when you're close to them by looking at the Signal Detected status near the top right of you screen. Use your Knife for this part, taking out the guard facing away from you and then the Commander. Continue to knife bad guys, working around the area in a clockwise direction. As long as you stay crouched nobody will be alerted to your activities.
Tip: If you're detected before you kill the Commander, he'll broadcast an alarm to call for help. Even if you opt to use your gun, try to ensure he's the first person you take out.
As it turns out, there's more than one Commander in this level. Head in the only direction you can until the Signal Detected is on your screen again. While it's almost certainly possible to stealth through this part, we pulled a noob move and got ourselves busted so we just shot everyone instead. It works just as well if you don't mind the alarm going off. Once everyone is down, place a charge on the giant door in the middle of the area to enter an underground tunnel.
Time to move onto your third Commander, who's just ahead of you. We also went loud on this one, but had the sensibility to shoot the Commander first so he couldn't sound the alarm. Once you've taken out all the bad guys in the area, head up the stairs, taking out anyone you see until you reach the top level.
When you reach a large Cannon with an operator on its left side, use your Knife to take out the bad guy. Head back inside to find a previously closed door has been opened, allowing you to go through and loot the area before moving on.
Continue to head in the only direction available, gunning down the opposition until you finally reach a second Cannon. Kill the operator, then turn it to the left and destroy the plane stuck in the side of the mountain. You must do this or you can't move forward in the level. Exit the Cannon and then head to where it was located, taking out any Nazis who stand in your way. When you try to pass through the door indicated on your screen, a giant robot dog will attack you. Just sit back and enjoy the fireworks.
After an inspirational chat with Fergus, climb up the wall, paying attention to the bad guys as they try to shoot you down. Take them out as they pop up, making sure to peek in any windows as you pass over. Keep in mind you can move left and right, avoiding enemies and machine guns rather than just passing directly over. Of course, when you reach the top, it's all up to you.
Drop through the floor and pull the lever, raising the gate so that Fergus and the rest of the team can get into the compound. Climb down the chain connected to the counter weight and begin to explore this maze like area. When you find a door that's latched shut, open it and two Commanders will appear near the top right of your screen.
As soon as you open the door, move away so the Commander doesn't spot you. Sneak behind him and take him out with your Knife. If he does spot you, just go crazy and shoot everything. This includes the two Kampfhund's.
The second Commander is holed up in a fancy dining room. If he knows you're there, he'll try to kill you as you approach, but he's really no trouble at all to take out. Once he's down, walk straight out of the dining room and all the way to the end of the hall, taking a left and walking across some plants to get to the next area.
When you reach the next area, just after being attacked by the Kampfhund, pull the sword on the statue to the left of the giant painting. This tunnel will lead you directly to a Commander who is chatting on the phone with someone. Interrupt him with a Knife in the neck. Exit the room, being careful not to alert the guard standing just outside. Leave him be, circling the area so that you can enter the room from another angle. Be sure to take out the two sleeping Kampfhund's. They won't hear you if you're crouched. When you get close to the Commander, take him out with your Knife. Of course, if you get caught, feel free to just shoot everyone.
Step out onto the wooden balcony and take care of any Nazis that attack you. Make your way around to the other end of the platform and go through the window. Keep moving forward until you find a big gun that allows you to mount it. Do so, then start mowing down anything and everything in the courtyard. If you run out of ammo, just pick up another gun and go back to work. Play close attention to what Fergus is singing as you're busy throwing down.
When you meet back up with your squad, grab the beam and clear the path ahead. Jump across the gap to the next platform to trigger a cut scene.
When you gain control, you'll find yourself in an incinerator. Grab the key out of one of the drawers in the corner opposite from Fergus and Probst. Use the key to open the door, then run back and grab the man Fergus refers to as Broken Feet, carrying him to safety in the next room. Well, safety may be overstating things a bit.
Time to do battle with one of the several death machine robot things you'll encounter in this game. This one is pretty easy, and generally they all have a weakness. Shoot the robot until it’s dead. One of your buddies will even tell you that his face is exposed. At this point you can shoot it in the face, or be cool like us and use your Knife on its face.
You're not in for a game changing cut scene. We won't get into the details, but you must choose to save either Fergus or Probst. Your choice will affect gameplay and story, so choose wisely. Saving Fergus will give you the ability to hotwire, granting access to health upgrades and alternate routes. If you save Probst Wyatt, you can pick locks, again allowing for additional routes and even armor upgrades. Seeing as how we had to choose, we went with Fergus simply because he was the most entertaining of the two characters.
When you regain control, approach and melee the armored beast to save Fergus, then jump on each of the tables and strike the incinerator nozzles with the pipe in your hands. Once Fergus frees you, head to the control panel by the windows and hotwire it. In order to do this, you must touch the wires together three times and then quickly jump out the window.