Halo 3 Campaign Walkthrough

Sierra 117

When you start the level just follow the mairnes, you will encounter a pack of sleeping grunts, just melee them all one by one, it will make this easier as apposed to fighting them, especcially on Legendary, keep following until you come to a small stream, get ready for your first proper firefight, two dropships will arrive, hide behind rocks and pop up to shoot, take one enemy out then duck and reload, continue this until you have eliminated about half of your foes, then move up to another rock, repeat this strategy,Now continue, you will encounter another small squad, nothing to hard, keep an eye out for the sniper rifle which is propped up on a rock, use it to elimante your opposition then move up, you will encounter a patrol, if you have any remaining ammo in your rifle use it then get up close and finish them off. Keep pushing forwards and follow your men, eventually you will come to a large water facility, clear it drop down to it but keep an eye out for a Brute Chieftan, it is wielding a gravity hammer so stay at distance, kill it then mop up the rest of the covenant, free your allies from captivity then hold off the rest of the Covenant until evac arrives, climb onto your evac as soon as you can.

Crows Nest

You will start this level without a gun, this is not a glitch! Continue to where you are told and recieve your weapon. Make your way the hangar and fend off the invading Covenant troops, use the turret to get an advantage. After this is done continue through the level and fight some more foes, you will come to a large hallway, this will be your first encounter with Buggers. They are fly like things and show no mercy, burst fire works best. After this follow and you will have another brief firefight. Now follow your objective, you will eventually come to a barracks were some marines are being held hostage, kill your foes quickly and you will be rewarded with some Marine backup. If the Brutes execute the marines before you free them you will not get any backup. Eventually you will come to a large dome platform and will meet up with the Arbiter, continue, remember, if you need to just hang back and let the Arbiter kill some of the bad guys, he can't die. When you come to a large lift let all your marines get on then go, you are about to need the extra firepower, watch out for the Jetback Brutes. Eventually you will come to another elavator, make a break for it and your done.

Tsavo Highway

When you start get on a Warthog with a turret and make sure a marine takes up the passenger seat and the gunner seat. Then drive out running over grunts, make sure you let your gunner soften up the brutes, if you need to hop out and scavange for ammo. Then continue, you will get outside, now make sure you keep moving or you will wind up dead. Carry on until you reach the bridge, you will need to abandon the Warthog and continue on foot as there is a gap and the only way across is a thin little support beam which the Warthog can't cross. When you get to the Wraiths kill the gunners, then approach it and board it, plant a grenade if you are having to kill it quickly but otherwise just melee it. You will need to continue, preferably in a veichle, when you get to more Wraiths just use the same strategy as before. Carry on and before you know it you will be done.

The Storm

Push forward in your Warthog, get out and clear the building then open the blast door up so that the Marines can get in.Go to teh long walkway and up onto the roof of the bunker, pick up the sniper rifle and sniper the gunners in the Wraiths, if you can nail some Brutes aswell, once you run out of ammo board the Wraiths and destroy them, mop up any remaining enemy forces then advance. When you come to the area where the Banshees are circling run up onto the walkway and pick up a missile pod, take the Banshees out, doing this will earn you the too close to the sun achievement. After you mop up most of the Covenant a Scarab will attack you, get a rocket launcher or another missile pod, take the legs out then board it from the back and destroy the core, you can also take the elevator up to the large platform, jump onto the scarab when it gets close then destroy the core. Make sure to jump of it quickly or you will be caught in the explosion and die. Now for the last section of the level, follow your marines into the bunker then exit with them, take any weapons and ammo you need then start attacking the Brutes, push forward slowly and you will come to a set of Hunters. Run to the high office and snipe them from there, hopefully your Marines will distract them. Now push forward, you will see the Covenant AA Cannon, suck behind rocks and snipe the enemy with your Battle Rifle or if you need to use an Assault Rifle, make sure to watch out for the Brute General with the Fuel Rod Cannon, kill them and destroy the AA Gun.

Floodgate

Start the level and proceed down the path until you come to a squad of marines who are being attacked by the Flood, carry n but make sure to stay at your distance, the Flood are brutal CQB fighters and will kill you quickly if you are not careful. Proceed through the level and you will see a flood form attacking a marine, kill it quickly and you will save the marine, if you fail the marine will be converted and turn against you, you must kill him in self defence if this happens. Continue and you will find a flamethrower, pick it up as it is lethal against the flood, ensure that you don't kill marines with this as it can be hard to control. Continue and the Arbiter will send backup,  you will now have a squad of Elites backing you up. Fight through the Flood and take your time, you will soon finish the level.

The Ark

Start off by deploying from the Pelican and follow the ODST's, go to the ridge and snipe some of the Brutes, focus on the Brute General. Mop this squad up then continue, carry on and proceed through the small structure then go outside, snipe an enemy or two then run to the crashed pelican and pick up the rocket launcher. Attack the Brute Choppers that come over the hill, wait until you have a good shot then a ttack the Choppers with your Launcher. Take them out promptly then push on. Keep going until you come to the large walkway with a Wraith and some SHade Turrets, keep circling around finishing off any enemies unfortunate enough to get in your way, you will need a veichle but this is not hard, follow the pelican above you until you come to another firefight, you will eventually come to a point where there are some Wraiths, take them out from behind, then a UNSC Frigate will drop some tanks off. Use them to push through your opposition, you will eventually need to take out yet another Scarab, use the same strategy as you did on The Storm to take it down, if you want get a Gravity Lift from the bunker and use it to board the Scarab.Take it out and get away from it then push up onto the structure, clear out your foes then go to the bottom floor, there is a squad of jump pack brutes waiting for you, stay behind cover and take them out one by one.Then watch the cutscene and run back through the structure to your evac.

Cortana

You will start the level with a Shotgun and Assault Rifle, gun down all the spores then use your shotgun on the combat forms, throughout the level Gravemind will speak to you, just carry on and ignore him. Keep shooting at the flood and keep and eye out for the Energy Swords on the dead elites, also make sure to use the Flamethrower well. Keep fighting until you come to a large circular room, kill all of the flood using the flamethrower and procced, eventually you will come to a room where there are three reactors, go onto them and shoot them then jump off, proceed out of the room and down into another room through a hole in the floor, remember that crashed Pelican on the way in? Head back there and EVAC, if you are playing alone the Arbiter will arive and help you escape.

Halo

This is it, the final level, run ahead and start fighting the flood, keep an eye out for the Combat Form with the gravity hammer, stay away from it and gun it down. continue up the slope and watch the left, there are pillars that flood tend to hide behind and surprise you from, get onto the tower and pick up the flamethrower, push through the flood and up to the top structure, you need to hold out for a couple of minutes so pick up ammo, Johnson will provide sniper fire, hold the flood off for as long as you can, then start running around killing them off one by one, once you are done and the blast door opens run inside and follow Guilty Spark (the lightbulb) into the room, then you will have to kill him, pick up Johnson's laser and fire it at Spark, he will die quickly. Watch the cutscene then run outside  to the warthog, use it to escape, now here comes the hard part, you must drive through Halo and reach the evac, watch out for falling panels, I can't help you as the path is randomized but my best tip is don't drive too fast or too slowly, once you reach the end you will have to jump onto the ship, game over, good job.