Act 1: Ashes - 2. Crumbling City
Don't worry about the first enemies, King Raven will do the job. You get the weapon of the game, the Lancer. Weaker than the Hammerburst, but has the cool bayonet you bought this game to use. You have to hold the B button and move toward an enemy to use it. Never toss the Lancer, if you can.
Now go up the stairs and when you round the corner take cover behind the railings in the open. Then blindfire your way to success; there are four Drones to beat, don't be shy to poke your head out and finish them off.
Pick up COG #4 on the ground across the way (your team tells you).
Pick up the ammo and Frags before the stairs. Go up and watch the scene. After its over, go and pick up the ammo and Frags to the left. Then Roadie Run along the left side of all these pillars to the space between the last and second-to -last pillar, with a Frag in hand. You should see an Emergence Hole begin to open to the right; aim a Frag where the ground shakes to close the hole before it even opens. Then take out the remaining grubs who should be chase by your team. Then pick up the ammo along the wall to fill up.
*Save at least one Frag, and you may as well pick up a Hammerburst.
Follow your team (press Y to locate) and then get ready for about four or so Drones to attack. They may rush, so be ready to practice the chainsaw. Then flank them from the right. After, continue to the gate and go the the left of it for some ammo. Then cross and do the Y press.
Go through the door and go along the left and be ready to toss a Frag to the ground where the statue sits. Plug up that hole quick and then take out the ones who survive. Don't proceed, instead come back to the door and go straight to mantle over something and reach some ammo and Frags. Then move through the pillars to the other side with a Frag in hand. Once you round the corner of the debris wall, quickly toss a Frag without aiming; if done correctly you will get it through before the pillar falls. If you don't do it correctly, you most likely will die; if you don't die, aim a Frag over the slab to close the hole. Kill anyone if they were able to sneak out.
Pick up COG #5 behind the hole.
When you exit the place, turn right and get the Frags and then continue to the dead guys.