Detailed mission walkthrough:
Once the movie has ended, press the TAB key in order to read the description of your first task.
New mission objective: Proceed to remote server room and access weapon database
You may proceed to the upper level. Once you're at the top, head on to the door on your right. Keep moving towards your current destination. You will probably notice a small robot on the ground. Sadly, you will have to destroy it right away, because it's a security mechanism. The robot is equipped with a flame thrower, so don't let it get closer to your character.
Two enemy soldiers will appear in this room. Take them out as soon as possible. Remember to use your suit in order to gain advantage over them. Also, you can always go back to the staircase and wait for them there. Head on to the room with the robot. I'm sure that you won't have any problems finding an adjacent office. Before you go in there, save your game.
There's a small room to your right. One of the enemy soldiers is standing there. Don't worry about the glass, because you'll be allowed to break it. Make sure that this enemy has been killed. Keep moving forward. You will have to turn right after a short walk. I'd strongly recommend saving your game there.
The next group is standing just around the corner. There's a large distance separating you from each other, so you should consider zooming in for a better view of the situation. Using the powers of your suit is equally important here, especially since some of the enemy units may actually try and get closer to your main character. Once they're gone, start moving forward.
You will have to find a small door which is the only exit out of this room. Keep going straight. You will come across a bigger door very soon (screen). I'd strongly recommend saving your game, because you'll take part in very difficult fights here.
Most of the enemy soldiers are currently occupying upper balconies. Move carefully towards the door. Wait for the door to open and start shooting at them. It would be a good idea to destroy some of the surroundings explosive barrels in order to get rid of one of these groups. More enemy soldiers will appear to your right. Keep firing at them. You should also consider retreating each time you've depleted your powers or lost too much health.
You will have to be extremely careful from now on, because a few soldiers will appear on the lower level and they'll advance to your position. As a result, check your compass in order to spot them. I'm sure that you cell the difference between the icons by now. If you're surprised by one of the soldiers, use a time stop function in order to ensure your safety.