Halo 3: ODST Mythic Guide - ONI Alpha Site

Halo 3: ODST Mythic (SLASO) Walkthrough by Daniel Morris

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ONI Alpha Site

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      Without a doubt, ONI Alpha Site has Firefight written all over it. Right from the get go, you are thrown right into an endeavor where the Covenant are flooding your bridge and YOU have to repel them. Then, you'll find yourself once again fighting them off from not one but TWO Firefight maps as you desperately try to keep the Covenant from getting their grimy hands all over ONI's darkest and most valuable secrets.
      All in all, this is a fun but also difficult mission. You'll have lots of allies here, but limited ammo towards the latter half. Use your heavy weapons sparingly as you'll need every last one of them to help you get through this storm of alien fury.
      This mission has been divided evenly into three distinct segments:

Security Zone
Alpha Site
Extraction Point

Now let's blow **** up!

Security Zone

When the mission begins, you immediately find yourself under heavy fire by Covenant Wraiths with an army of infantry charging over the bridge towards your platoon. The situation seems grim, but fortunately you have a contingency plan already in place. The bridge is lined with explosives, and all you need to do to set things in motion is activate them. So right from the get go, go ahead and arm the last two charges. Then scale the guard tower, take the sniper rifle, and wait for the Superintendent to reluctantly give you the okay for detonating the bridge. Now laugh as the Grunts explode like popcorn kernels and go flying through the air. Haha!

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Continue to watch out for the falling mortars as you make your way towards the blast door. It's about to open, sending you into your next zone. Get that Spartan Laser ready! As soon as the doors open, take aim at the Phantom's side gunner as it prepares to land. Fire! This will save you from getting pegged by plasma projectiles. Next, it will drop off a pair of Hunters. One laser shot each should do the trick! Save your last two shots for the nearby Brute captains, and help your Marines allies mop up the rest.
At this point you'll want to acquire a magnum and as much ammo as you can. Yes, that means betraying your Marines if necessary. You should also note that there are two additional Spartan lasers in this area. One you'll be needing for the current battle, and the next we'll be using later. Go ahead and grab either of them. They are located near the highest elevation segment. Once your Marines have finished off the current wave, the Phantoms will start to swarm. Use your laser to take out the Brutes as soon as they land. This will make the battle fly by much easier and put you in less of a bind. When you're out, you can use the typical plasma pistol/magnum combo to mop up the rest. At that point it shouldn't be too difficult since their numbers should be reduced drastically.

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At some point, you'll hear one of your allies yell "Chieftain!" which is your cue to rush inside. Grab the other Spartan laser and juggle it with the nearby rocket launcher (behind the wide pillar between the two building entrances) to the buildings interior. Hand the launcher over to your ODST buddy to help you in the coming battle and grab additional magnum ammo from one of the Marines that made it inside (presumably as Sargent). Now you're ready to fight with your back to the wall yet again...

Alpha Site

      In case you hadn't already guessed, the ONI lobby is the second Firefight map from which this mission is based. And yes the battle that's about to ensue resembles the experience quite a bit. The skirmish itself isn't all that difficult. The real problem is making sure you have enough ammo to down all your enemies. Plasma weapons can be tough to come by at this stage of the level, and considering the number of Brutes you are about to face, this can make this situation appear to be extremely grim. Lucky for you, there's a Spartan laser strapped to your back to help you cut their ranks for a more even fight.
      Get comfortable with your surroundings. You'll notice four entrances to the lobby. Two of them are currently closed blast doors (hint hint), and the remaining two are completely open and leading towards the rear of the building. YES, you will have enemies coming from all four, but fortunately they won't be doing it all at once, so no worries in that department.
      Again, the key to winning this battle is to using all of your available ammunition sparingly, so make every shot count!
      First up are the blast doors. You'll hear a Marine give you a warning that the Covies are cutting through. But don't lurch forward just yet. The second those doors open, a flood of kamikaze Grunts will come scampering through wildly. A well placed magnum bullet should cause a chain reaction that kills them all. Next, they'll be coming in through the remaining blast door. Same deal. Your main concern here really isn't protecting yourself so much as it is your allies. It won't take much to send them flying through the air and down one of the elevator shafts. Remember, the longer you can keep them alive, the less you'll need to worry about ammo. PLUS, you'll have a decent distraction on your hands while you flank the enemy.
      After the waves of Kamikaze Grunts, the Covenant forces will become much more organized. Brutes will be leading squads of Grunts and Jackals in to mop up what the crazies couldn't. Use your Spartan laser to take out the Brutes. Since you have five shots, you should be able to kill at LEAST five Brutes. Sometimes you'll even luck out and manage to land a two for one type deal. You can use the rear of the lobby (the part that leads outside) for cover. You'll also notice a few hemo packs underneath one of the wall plaques if you need them.
      Your rocket ODST should be doing a fair job at mopping up the cannon fodder at this point so concentrate on the stragglers. Once you've thinned their lines enough, make your way to the blast door side of the lobby and commandeer any plasma weapons you find to mop up the remaining Brutes. Save some ammo though, because you're far from finished. The next video demonstrates how the blast door half of this battle should go.

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You'll get a short break before the second half of the battle commences. So take a moment to note the locations of all fallen plasma weapons. You'll be needing them. A few seconds later, Phantoms will begin dropping off reinforcements from the open side of the lobby. These guys are far more dangerous as they will be wielding Brute shots, so try not to stick too close to anything that could ultimately result in you being killed by splash damage. At this point your goal should once again be to thin their ranks enough to allow you to cross over to their side and get behind them. Try to combo-kill as many of the Brutes as you can. Again the end result should look something like this...

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If you start running low on plasma ammo, use plasma grenades and spike grenades as needed. The rocket ODST should also be doing a fair job at helping you scrape up the little guys as well.
At the close of the battle, an elevator will arrive to transport you to the top of the building. Hey, it's still better than being stuck in a room covered in Covenant and C4...

Extraction Point

As the lift ascends, stick close to the door and duck. Within seconds you'll hear the familiar chittering sound of Drones as they surround you and your allies. The good news is as long as you lay low, they shouldn't present themselves as being too much of a hassle. A few pop shots will bring down the stragglers. The lift will screech to a halt at the top of the ONI building where yo will be met with an exit on either side. A Pelican will be waiting for you on the far side. The only thing standing in your way at this point is cannon fodder, a cluster of Jump-Jet Brutes, and—oh yeah—a Hammer Chieftain.
You'll be able to kill most of them from the doorway as long has you manage to avoid the deadly grenade spam from both parties. You should have plenty of plasma pistols to work with at this point, so ammo shouldn't really be any issue in terms of combo-killing the Brutes. And there's more than one way to deal with the Chieftain. You can either side-step his swing and assassinate, OR you can let the rocket ODST do all the work for you as shown in the next video...

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Once the area is clear, you can now safely board the Pelican and watch the fireworks show.

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