Start by heading to the middle of the room where there will be a tower jutting out in the air. There will be a few enemies that will surround this tower as well as the areas around so make sure to get rid of them. When you’re done, go to the opposite side from where you began and hop onto the pipe and to the outside of the factory. At this point, there will be a Gold Orb nestled in between 4 silos standing together. Make your way into the set of double doors on the other side of the area and activate the Blue Device. At the foot of the spiral staircase is a Devil Trigger reviver, use that along with Aerial Heart to fly to the top of the support beam to collect Flame Heart. Then leave through the door near the bottom of the room where you’ll be greeted with a group of Flambats. Jump onto the small platform in the lava pit where you will find a new room. Inside, there is a new sword Vendetta to your left but other than that, nothing else inside is usual to Dante at the moment. When you’re outside now move onto the right portion of the area and find the Secret Mission which is partially obscured by some crates against the wall. After the Secret Mission don’t leave yet, by jumping on the support beams, find the platform in the corner holding a Blue Orb. Enter the door at the top of the stairs to continue on down the elevator; watch out for the Blood Goats waiting for you at the bottom. Proceed into the large trolley that will take you into the Oil Field while you hack away at the enemies inside. Hop onto the other elevator again and before you enter the door with the red light above, inspect the door on the left for a Secret Room and then leave.