Begin by jumping up the platforms. Try to never be in the line of sight of more than 2 gauss turrets at any time. Try to stay on the left side, as it's easier to scale the left wall than the right. Once reaching the top, Jump across to the platform with the circle of gold. Watch out, the gauss can still shoot you here. Wait for the Zap drone to move so you can go in the tunnel. Be careful in here. Hug the walls until you can make a move. Get the key and get out. Jump down to the second drone tunnel. Unless you're feeling greedy, in which case, be careful with the rocket. This drone spot is easier than the first. Wait for them to pass you by, and then move quickly. This strategy can be shown more clearly in this demo file (Instructions for demo)