1. Infiltrate the base
2. Steal the plans
3. Enter the main facility
O b j e c t i v e 1:
Walk forward until you come into view with the gate. Zoom in with your sniper and shoot the sniper in the lookout tower and the guard by the gate. Some dude will now radio and command you to protect him while he opens that gate. He's going to get shot, either way, so once he opens the gate/gets shot go into the house he radioed you from. Take the health (or remember it) and a brief breather, as you'll soon need it.
O b j e c t i v e 2:
Make your way through the cold, stopping frequently to shoot snipers and those REALLY annoying animals called dogs, to a building with a red door. In other words currently the only operable door in the base.
Go up the stairs, take out the two-three sentries up there and grab the plans from both rooms. Next continue into the main hallway and toss a few grenades into it. Turn left at the corner into a room to face three guards, so take cover behind the funny looking machine. Take 'em out and proceed past the machine into a room at the other end. Grab the plans and stay still.
O b j e c t i v e 3:
As of now, 5-7 guards appeared and will soon attack. Just let them come to you, one by one taking them out. Once that's over with head back downstairs to a newly opened door.
There are two or three guards in the hall on your left, take them out by peeping around the doorway and firing with your Springfield. As soon as you do, a door in front of you will open and a guard will come out firing. Be quick to the draw, then hurry into the room he was in. Right when your there, turn around IMMEDIATELY with a loaded machine gun because a dog will be ready to knaw at you if you don't kill it. Exit the room into the main hall.
Turn right at the corner, take out the guards from both rooms and the two in the hall then move on. Cruise along until you come to a door in which leads outside. Don't exit indoors yet. Take out your Springfield and crouch near the door. Move closer to the outside edges until you can see the brown of a nazi uniform in the distance. There is another right by him, so take them both out. There is one more sniper in the distance, visible once you exit into the cold, but he's got rather slow reflexes. Run past all the barracks and turn left at the end. Kill the guard. Where he was, there is another corner with two more sentries.
Here we see a situation involving lots of crates. Don't worry there's only one guy awaiting Powell and once you can see the crates, you can see him, pathetically hiding behind a telephone poll.
Past the crates, you will see the MG42, and when you do crouch. And I mean RIGHT when you see it crouch. Go up to the wooden box by the MG42 and take out the sniper rifle. Peer around the crates (WHILE CROUCHNG!) and put to death the first two snipers you see. Now, go up to the MG42. Stand up, take hold of it, and fire at the two dogs and many people below. Make sure the dogs are your first target, since those are the fastest and most deadly.
Once they're all taken care of, travel down the path to where you shot at them. In the first building where you killed the snipers, there's a ladder in leading up to a room which contains a room with a 50 health and some ammo/grenades. If you don't need those, keep heading straight to a door in the distance.
Use the peer-around-the-corner technique to take out most of the "slime" in here. Continue up the stairs, through the door, and down another set of stairs. Once at the bottom, open the door.