The Pillar of Autumn (Halo: Combat Evolved level)/Walkthrough

Weapons

 * Pistol
 * Assault Rifle
 * Plasma Pistol
 * Plasma Rifle
 * Plasma Grenade (Heroic and Legendary only)
 * Fragmentation Grenade

Vehicles

 * Warthog (cutscene only)
 * Scorpion (cutscene only)
 * Pelican (cutscene only)
 * Longsword (cutscene only)
 * Bumblebee Escape Pod (non-drivable)
 * Halcyon-class Cruiser UNSC Pillar of Autumn (non-drivable)

Equipment

 * Overshield
 * Health Pack

Part 01: Reveille
Climb out of the Cryo tube. Do your Aiming Diagnostics Test, then your Shielding Diagnostics Test. Then, exit the room with the technician. The man will run towards a door, he will die. Don't bother following him, it's a waste of time, find your own way through the pipes by jumping over them, and you will see another corridor leading to your objective. It's simple and straightforward.

Now, follow the Marine who will lead you to the bridge. He will stop to kill some Covenant, but you just have to follow the corridor to get to Captain Keyes.

Part 02: AI Constructs and Cyborgs First!
As you leave the Bridge, your Pistol will appear. Your first three enemies in the game are two Minor Grunts and one Major Grunt. Take them down with your pistol (try practicing some headshots); it shouldn't be that hard, even for a beginner. Reload your pistol and walk into the cafeteria, and you will automatically pick up an Assault Rifle. Take down all the enemies in the room, you can also duck behind some steel barriers and let the incoming Marines (accompanied by Johnson) take down the Elites. You can also hide behind the steel barrier to snipe down Grunts and Minor Elites with your pistol's scope. Head-shots are practically useless against Elites unless their shield is down.

Once the room is clear, swap your Assault Rifle for the Plasma Pistol. Now, exit the cafeteria. By now, your weapons should be the Plasma Pistol and a Pistol. The advantage of the Plasma Pistol is that it does not need to reload, and can take down Elite's shield with one charge bolt, and a practical endless supply, but the disadvantage is that it can overheat and run out of battery quickly.

After preparing weapons and all, follow the hall until you come to an Elite who foolishly has its back turned to you. Melee to kill him instantly and proceed. Continue onwards, and you will reach two Marines about to be killed by a Covenant boarding party. Don't go near the Marines unless you want to either die or lose most of your health. Anyway, when they come out, charge your Plasma Pistol at the Elite(s) (the number of Elites depend on chance) and take care of the rest with your Pistol. Go inside the Covenant Boarding Ship and pick up the Over-shield. An Overshield will project itself over your shield and triple its effectiveness.

Then proceed into the dark hallway. Some survivors of the last skirmish might still be here, so beware. Use your flashlight when necessary. In the next hallway, you'll see some Marines firing. Instead of joining them, turn right. A panicked Grunt will come running towards you. Kill him. You'll find yourself in an ideal flanking position. Use your Pistol to take them down, and use your Plasma Pistol to take care of the rest.

Swap your Plasma Pistol for the dead Elite's Plasma Rifle. After the battle, continue through. A Plasma Grenade will kill your Marines, so don't go near them... yet. Now, proceed through and use your Plasma Rifle to take down the enemies which consist of a Minor Elite and several Grunts. Swap your Plasma Rifle for the Plasma Rifle that used to belong to the now-dead Elite.

Go into the next hallway, which will be infested with Covenant. Use a mixture of Plasma Rifle bursts and Pistol rounds to take them down.

The next area will have some allies fleeing from a group of Covenant. Kill the Elite first, as he poses more of a threat towards you and your allies. Then, melee the Grunts to death, it's a waste of ammo trying to shoot them down here.

Continue through the hallway. It'll lead you to some stairs with enemies scattered everywhere. Doesn't matter; take them out with your Pistol scope and your Plasma Rifle when they get close. Bear in mind that you must always swap Plasma weapons frequently. Swap your Plasma Rifle for another Plasma Rifle with more battery. After you have finished the enemies on the top level off, there would have been another Minor Elite and more Grunts on the bottom level, however, they are no matter. Take them down with your Plasma Rifle. Go back up the steps and continue on through the doors. There should be a heap of enemies here. No matter, you have your Marines to help you, if you haven't killed them yet. Take the Health Pack if necessary. Retreat when your shields are down.

In the next hall, there will be about seven Grunts and an Elite behind a Covenant Shield. Take the Grunts down; the Elite will ignore you unless you come up close to him. Take the Grunts out with your Pistol and take down the Elite with your Plasma Rifle.

Keep on proceeding, eventually you'll meet Grunts a fair distance opposite from you. Scope in and put the Grunts into a permanent trip to sleep with your Pistol. Then, proceed. Cortana will tell you to follow the NavPoint into the airlock.

Use your flashlight to find your way through(or if you're daring, you can pop in and out to take pot shots at the enemies). After you have found your way through, melee the door, walk forward; turn left and melee the Grunt with your weapon. He will die instantly.

Next, there will be a bunch of Covenant. Kill them with any method you please. Replenish your Plasma Rifle.

Continue down the right way and you'll reach the blackened and charred hallways of the ship. The lone Major Elite at the end of the hall shouldn’t have spotted you yet. Keep your distance and scope him with your Pistol. If the Pistol won't kill him, then the explosion will. Go into the charred parts of the room. Another explosion will occur, killing all but maybe a few Grunts, don't pay any attention to them, and go into the airlock.

There will be two Grunts, melee them. Then, use your flashlight to aid your way through.

Eventually, you'll reach a place full of Marines fighting Elites and Grunts. Take them all down.

Continue through. You'll be opposite some barricades, and some Frag Grenades. Pick them up, and throw them onto the other side, which will be full of Grunts and one Major Elite. Once they are all dead, jump over the barricades, and go into the lifeboat.

Part 01: The Pillar of Autumn
{Cinematic}

Part 02: Reveille
This first part is easy, but don't let that give you a bad impression of the game. For now, just follow the Marine's instructions carefully. Aim at the flashing panels and charge your energy shield. After that, Captain Keyes will order Master Chief to the bridge, skipping your weapons training. His friend will run out of the cryo bay, asking you to follow him.

Instead, jump over the pipe, turn right and go down the hall. There will be another dead technician in front of the door. Go forward, and you will trigger an explosion from a couple of burning pipes. It won't drain your shields though. Go through the door and crouch below a half opened blast door. The scene behind is utter chaos. Two Elites are firing at a group of innocent technicians, but the blast doors will eventually close and trap the Covenant inside the other room. Go through the only door in the place, and enter the dark hallway. You might want to activate your flashlight by pressing the white button (or by pressing Q if you're playing on a PC). After the door opens, a Minor Elite will roar at you, but he'll retreat when shot by two Marines. Proceed onwards. Then you will meet a Marine that will lead you the rest of the way to the bridge. Walk towards Captain Keyes and trigger the cinematic.

Part 03: AI Constructs and Cyborgs First!
Get out of the bridge to the hallway you came from. Your Pistol should activate, and some Grunts will appear in the hallway, panicking when they see you. Melee them to conserve ammo.

A door will open, and you'll see several Marines fighting a group of Grunts and an Elite may vary depending on the difficulty. Pick up the Assault Rifle, reload and start firing at the Elite, spraying and bashing until he goes down. Mop up the rest of the Grunts as well.

Additional groups of Covenant will pour in from an open door on the other end of the hall. Two Elites and lots of Grunts will be there. Zoom in with the Pistol and take out the Grunts with headshots and rapidly advance on the attacking aliens. Spray the Elites with Assault rifle fire and melees until they are down. Beware however, as these guys are very strong and can whack you to death. Proceed to the next room, paste the walls with Grunts and carry on. You might want to try out one of the Covenant plasma weapons. Try them out and see if you like them. You can't reload them but they're a lot of fun and are powerful indeed. After preparing weapons and all, follow the hall until you come to an Elite who foolishly has its back turned to you. Melee and proceed. Continue onwards, and you will reach two Marines about to be killed by a Covenant boarding party. Charge in, whacking, shooting and decimating anything that moves. It might be intimidating if it's your first try but it's a lot of fun. Remember you do have Marine back up. After the fight, pick up one of the Overshields at the end of the craft. Then proceed into the dark hallway. Some survivors of the last skirmish might still be here, so beware. Use your flashlight when necessary. In the next hallway, you'll see some Marines firing. Instead of joining them, turn right. A panicked Grunt will come running towards you. Kill him. You'll find yourself in an ideal flanking position. Spray them with bullets and retreat when you need to reload. The aliens, not able to withstand the crossfire, will soon fall back. Engage and annihilate as they do.

After the battle, replenish your ammo and supplies, and continue on. A Plasma Grenade detonation will kill a Marine in the passageway in front of you. Turn right and aid the Marines in killing the Covenant. The next hallway will be infested with a healthy population of enemies. Deal with them any way you see fit, taking cover when your shields are down. After you've killed the entire Covenant in the vicinity, go inside the Boarding craft and retrieve another one of them. The next area has two desperate unarmed technicians fleeing from a menacing group of nasty aliens. First, deal with the covenant on the right, taking down the Elite's shield and bashing him to death. Or for a change, use the deadly pistol combo. Melee the Grunts as well. Then focus on the Grunts and the Elite on the left. Then go back left, and get one of those Health Packs if needed. Continue.

Next part: The stairs. This might seem intimidating but it's not. At least not on Normal, on Legendary this part is a pain in the ass. Put your pistol to good use on the Grunts while climbing the stairs. Once on top, proceed to spray the Elites with gunfire as well as the Grunts and Elites that appear. After you've finished those off, kill the remaining Grunts downstairs. You'll immediately notice the many dead bodies of Marines lying here. Further down the hallway; the perpetrators. Avenge their deaths mercilessly. In the next hall, there will be about seven Grunts and an Elite behind an Energy shied. Kill him with the deadly Pistol combo. When proceeding you'll notice a life pod being destroyed when you look out the window. Kill the Grunts guarding the airlocks and proceed to the NavPoint Cortana gives you. Use your flashlight to find your way in these cramped technician's hallways. When you emerge, knock down the door and walk forward, melee the Grunt while you're at it. You can choose to pick them off here one by one, or instead charge in and blast them. Or yet again shoot one and see what happens. Take them out any way your heart desires. Continue down the right way and you'll reach the blackened and charred hallways of the ship. The lone Elite at the end of the hall shouldn’t have spotted you yet. An explosion should be triggered, half draining the Elite's shield and making him easier to kill. The ensuing explosions will kill the Grunts nearby. Go into the tunnel, turn right, and kill both Grunts lurking there.

Emerging from the tunnels, you reach a place where an Elite and lots of Grunts are combating Marines. Like most fights on this level, there is no real strategy. Surprise your fellow creature/alien/animal and whack him in the side. Finish off the Grunts while they run for cover and continue on ahead. After a lot of Grunts you'll reach a barricade chock-full of Covenant bad guys. You can flank them by going into the hallway on your right or just shoot them from where you stand. When confronted with large groups of enemies, your first priority should always be to reduce the incoming fire as much and as fast as possible. That being said, aim for the Grunts and take them down. The less guns shooting at you, the less distraction when dealing with the Elites. After mopping them up, you'll reach yet another barricade. The final one. This part is pretty fun. Pick up the fragmentation grenades. There's a group of Grunts and a Major Elite on the other side. After you're done, walk to the lifeboat and enjoy the cinematic.

See a walk-through of the level. It is divided into two parts: [|Part 1] and [|Part 2].