Devil May Cry 4/Porte de L'Enfer

Opera House Exterior
The cutscene shows demons attacks citizens of the town in the plaza. Credo leads them to a gate and leaves Nero to kill the demons. There is not much in this area, just kill of the scarecrows and move on. Red orbs are contained in the benches, smash as many as possible. The door to the storeroom is at the end near the floating red orb. You will receive a tutorial if they are turned on.

Storehouse
As soon as you enter this room there is an opportunity to gain a precious gold orb. It is in a small hole in the wall at the top of the small steps. Just climb the wall to get it. After this climb the main stairs to the upper floor. In this room three scarecrows will ambush you and they must be killed to proceed. Red orbs are hidden inside all of the boxes and shelving units.

Business District
Nothing to do here. There is a small army of scarecrows smashing up the city below but there is nothing to do about this (for now anyway). Enter the Cathedral through the door on the left.

Cathedral
Head to the lower section of this building. Down there are some chairs that can be smashed for red orbs and the Evil Legacy skull, granting the ability to use Snatch and Grim Grips. After picking this up go up a floor. There is a Vitality Star S in one of the sections, snatch it with the devil bringer to pick it up. There is a green orb on the other side if you need health. Follow the grim grips to the exit, being sure to smash all of the benches along the way. There is also a large red orb on the left at the exit, obtainable by snatching it. You can jump across to get it but then you fall back down to the bottom of the Cathedral.

Business District, Terrace
You can now grapple across the street to the other side. Over here is the entrance to the first secret mission, Annihilation. Past here is a section where you will be ambushed by two scarecrows. Dispatch these and grapple across the street and there are more scarecrows to be killed. Through the door is the entrance to the Residential District.

Residential District
Drop down here go round the corner. On Son of Sparda or higher there will be assualts or scarecrows if the difficulty is set lower. The boxes contain red orbs and there is a gigantic one in the upper area. Just past this there is a way up to the rooftops. Go through the arch and smash the bins then go straight, this section leads to the Port.

Port Caerula
The way forward is blocked because the bridge is up. To lower it you need to grim grip across the port and into the customs house. There are a few scarecrows in here, after defeating them activate the switch and smash the blue web. Hop up the stairs and through the door at the top. In this bit hit the switch to lower the bridge. Then backtrack to the bridge and cross it into the next area. This time there are two groups of scarecrows blocking the way, one outside the customs house the other just before the bridge.

First Mining Area
In the trench at the end of this room is six red orbs. Grip up to the upper level. There is a divinity statue by the door, so buy vitality stars and power up before the next section, the Ferrum Hills.

Boss Fight: Berial
The flaming giant Berial is in this section. The wooden houses in this area are destroyed quite quickly and contain a small number of green orbs to boost your health. The table hopper skill can be used to dodge almost all of Berials sword attacks, the only one that requires any else is the attack in which he intensifies his flames, hitting the close area around him. Use sword combos the hit his body as this can leaves plenty of time to dodge his attacks and does a lot of damage. Useing the air hike ability to jump up and attack his face will do even more damage, but leaves Nero more vulnerable to either a sword hit or a punch. When the flames are extinguished, jump and grab his head with the buster to slam him into the floor and then buster him again to throw him across the arena. After this he usually reignites the flames which can hurt if you are too close, but it is sometimes possiblr to get a third buster combo in before this happens. On Son of Sparda mode, Berial gets one additional attack, a lunge across the arena to hit Nero on the other side, which he typically uses after the first round of buster combos. This can be table hopped, but it has to be timed well as the build up is long and dodging too early will result in being hit by his most powerful attack.

Post-Berial
Not anything major left to do. Just go up the stairs behind where the red web was and into the tunnel to end the level.