Hint: Defeating Super Soldier (first meeting)
The Tesla weapon will take you out quickly if you do not get out of its line of fire. Jump the railing to the right and get behind the window. He cannot seem to see you at that location. Blast it with whatever rockets you have left, then try luring him behind the window so you can move around the rest of the room to get the armor and med kits, as well as kill the enemies on the catwalk. You will have to take potshots at the Super Soldier until it starts limping for a better chance at hitting him with grenades and machine guns.
When fighting the Super Soldier with the Telsa Gun, while he is in the computer room under Deathshead, run up the stairs to the catwalk. Stop directly next to the door where Deathshead is talking in that room and get the Super Soldier's attention. When he walks under you, fill his head full of bullets. A few bullets should kill him. This is much easier then continually shooting him in the armor.