Secret Level 2: Asteroid Military Depot
Enemies: Super Hulk, Cloaked Hulk, Driller, Cloaked Driller, Supervisor Robot
This is a small, square mine with prison cells and Robot Generators in the center. Fly forwards to pick up the Cloaking Device and then fly around the outskirts to kill all of the Drillers.
If you go through one of the doors to the central area the Robot Generators will trigger. Instead, whenever you want to enter the central room fly through the tunnels in the roof. Take out the Super Hulks and pick up the Red Access Key.
To get into the cells and rescue the Hostages shoot the cell door from inside the central room. Quickly fly around and enter the cell. The cells doors only open from the inside. Do this for all four prison cells and then get ready for the reactor room.
Reactor: Open the Red Door and shoot the reactor from here. There are a few Super Hulks but they shouldn’t cause any trouble if you’re far enough away.
Exit: Up through the passage in the roof and then up to the exit.