Infinity (Halo 4 level)/Walkthrough
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Welcome to the jungle's of Requiem. Anyone who's seen the trailers for Halo 4 will remember this level. Well, some of it, anyway. The real deal is quite different.
You begin your trek with an Assault Rifle and a Pistol. As soon as Cortana marks the waypoint for you, start following it, deeper into the jungle. After a short walk, you will come across a trio of Promethean Knights standing over the bodies of several unfortunate Marines. Hold your fire; they'll teleport away before you get close. Move to the waypoint and use the "reload" button to access the IFF tag on the ground. Before you leave, be sure to grab the DMR on the ground, swapping it for the pistol (or the Assault Rifle if you feel you can do without automatic fire). There is also a crate of Frag Grenades a bit further on beyond the bodies. Grab them.
Once you are properly armed up, walk down the path to the left of the dead bodies until you encounter a small pack of Crawlers. This is what the DMR is for; a single, well-placed shot to the glowing mouth will destroy any Crawler, no matter the rank. Several body shot will also yield the same result. Eliminate them quickly, but don't move on just yet. Jump down to where they were and go to the left, under a tree arch. Laying in the water next to a Marine corpse is another excellent weapon for the road ahead; a shotgun. Retrieve it and continue forth.
The first part of the path ahead is relatively linear, with groups of Crawlers appearing every so often to challenge you. Primarily use the DMR to dispatch them. You will need your shotgun's ammo for later targets. Said targets are Promethean Knights, which will apear along with the Crawlers as you move deeper into the jungle. These Knights will deploy Watchers for combat support. In these engagements, your combat priorities should be as follows;
If the Watchers are not eliminated first, any Knight that is brought down can be resurrected. And, in turn, any Watcher that is killed can be replaced by another deployed from within a Knight. Both must be killed in quick succession. Which is where the shotgun comes in. Eliminate the Watcher with the DMR (it should take only four or five shots), then charge the Knight and shoot it twice with the shotgun to take it down. Then, move on.
This pattern of combat will continue for a short while, with small groups of Promethean emerging to engage you. Kill your way through all of them, grabbing additional ammo as you require it. Keep your eye out for Marine corpses; there are always weapons nearby. And, of course, there's no taboo against grabbing a Suppressor or a Light rifle off a downed Knight...
After about two or three of these engagements, you will come across an altercation between an unlucky Marine and a Knight. Hold your fire; there's nothing you can do for the soldier, but he will not perish in vain. Cortana will mark the object (a Promethean Vision armor ability) for you. Its heavily suggested you take it, as the section of jungle below you is choked with blinding fog. Combine Promethean Vision with the Binary Rifle (also dropped by the Knight) to clear out your path ahead, with your primary target being the Knights, then the Crawlers. Reload on grenades should you need them from the crate to the right.
As soon as your path is clear, jump down and more ahead. More enemies will emerge from the fog; use PV to find them and any weapon you deem fit to eliminate them.
Cortana will make a comment about another IFF tag on the far side of "the thicket". This part can get a big confusing. To help navigate, always try and climb uphill. You will know you're going the right way when you encounter a small pack of Crawlers. Lob a grenade into their midst from above them and clean up the stragglers and move on until you hear Cortana mention the IFF tag again and something about a "dead end". Don't worry...its anything but. Fight your way through the last few Crawlers (making sure to watch the trees above you, as they can climb) until you reach the objective waypoint. Grab the ammo by the door, activate the IFF tag on the ground and sit back as a cutscene activates, reuniting Chief with an old friend...
Once the scene ends, move out towards the objective. You've got friendlies now; two brave Marines willing to fight by your side. Make it worth their while; swap out their assault rifles for whatever superior weapons you're carrying. Don't worry about getting stuck with them though; there's more ammunition outside, including DMRs, an Assault Rifle, and a shotgun on the ground. You will be greeted (surprise!) by Crawlers, and one or two Knights. Kill them all, using Promethean Vision to find any stragglers before moving ahead. With that first group cleared, you will find yourself almost immediately in the midst of a Promethean vs. Marine battle. Clear the area, but be sure to grab the Railgun leaning against the sandbags to the left. Its spectacularly useful against Knights, able to one-shot even the toughest ones that are sent against you. There are armor abilities in the crate next to it as well, (two Holograms). Grab these if you wish and spam it towards the enemy; the Promethean will be distracted long enough for you to get a good hit on them. Much more useful is the Autoturret picked up from a Knight. Deploy it in an area with good cover and let it deal with the Crawlers.
Fight your way up the hill through the Prometheans to the door. The "interface" Cortana mentions is to the right. Go to it and plug her in, then settled down for a bit of a support fight.
The Prometheans will come at you in waves; make good use of the Machine Gun turrets mounted on opposite sides of the door to mow them down. Deploy your Autosentry to help as well. Try and keep the turret on its base if possible; infinite ammo is much more useful than 200 rounds. There should be several Marines with you as well; they'll help with the Prometheans. Give them good weaponry (DMRs, the Railgun from earlier if you haven't used it all, Lightrifles, the like) if you can.
After you have beaten back several waves, the doors will open. Retrieve Cortana and move ahead. The Marines will stay behind to watch your back.
Move through the cave till you catch sight of another Knight. But hold your fire...he's not facing you. In fact, he's not doing anything threatening...well, not to you. He's ordering a bunch of Grunts around.
Once Cortana and Chief have had their little chat about this, go ahead and attack. If you move fast enough, you can catch the Knight with a melee before he teleports away. If not, kill everything in your path as normal. Don't hesitate to grab the Railgun to the right of the entrance, by the wall, and don't be shy with any grenades you have saved up. As soon as the area is clear (several more Knights will teleport in after you kill the first group, and a Phantom will come by to drop re-enforcements for the Covenant), a Pelican will arrive to extract you. The fun isn't over yet though...you're just going to the crash-site of Infinity. You need to help take her back.
Stepping off the Pelican, you will be rearmed with a DMR and an Assault Rifle. Even better, you're not alone; there are several Spartan-IVs at your side now. And, to sweeten the deal, a Scorpion tank lays at the base of the ridge you are on. Clamber aboard, let the IVs mount up too, and roll on towards the objective (be careful of the Warthog driving around as you do.)
A Phantom will appear, dropping several high-ranking Elites and a clutch of Grunts. Obliterate them, but be wary; several Ghosts will approach as you fight. Destroy them and roll onward through the debris-filled trench leading to Infinity. More Ghosts, sniper towers, and even a few Wraiths will block your path. Blast through them till you reach the objective waypoint; an elevator large enough for your Scorpion to roll onto. Do exactly that and ride it into Infinity.
The bay you come into is under attack; put your Scorpion to use clearing it out (be careful not to shoot the Marines fighting back the Covenant boarders), then clamber out of your Scorpion. You can't go any further in it...but you're about to get something even BETTER. Follow the waypoint that comes up to the storage bay and activate the panel. This will release a fun new to for you; the Mantis combat walker. You can climb straight in and start the fun, or pause to grab one of the many rocket launchers laying around the base of the platform before you do.
Once inside the Mantis, Cortana will give you a quick little intro to her weapons systems and controls. Shoot out the door ahead of you (keep your eye on the machine gun's heat as you do) and stomp forwards into the belly of Infinity.
The path ahead is long, and filled with Covenant and Prometheans. In addition to infantry, the Prometheans have brought along hard-light turrets. Put the Mantis's two weapons (the machine gun and the rocket system) to good use clearing everything out, and if any of them happen to get to close, use the "melee" button to overload the Mantis's hydraulics and smash them aside with a might stomp. Don't hesitate to shoot walkways with enemies on them as you move ahead; the walkways will come apart, killing those taking cover upon them. The end of your path is another elevator, one that has several Covenant inside. Clear it out, board it, and ride it up to the top deck of Infinity. Listen to Lasky's transmission on the way up; he'll inform you of what you need to take out once you're outside.
Exit the elevator (the door is on the opposite side of where you came in) and come out onto the dorsal side of Infinity guns blazing. There's no shortage of targets here; infantry, Banshees overhead, and a few milling Phantoms. Ignore most of these and prioritize the three waypoints that Cortana will mark for you. Two are within easy sight-line of your exit point; don't go wading into a fight if you can just shoot your target from afar. Make good use of the Mantis's missiles; a full five-round burst will kill just about anything. Each target you destroy will give you more aid in your fight as formerly jammed defense systems come online and open up. During your fight, several Phantoms will arrive, carrying additional enemies. Ignore the Phantoms (though the Mantis is quite capable of eliminating them, it takes far too long) and kill whatever they deposit until the third and final target (which is under the massive MAC gun directly in front of you, and requires you to go around and down) is down. As soon as it is, return to your original position overlooking the whole area and open up on the Banshees, Phantoms and dropped troops that come in. Once you've driven off the last of them, there's one final task for you; reset the MAC EM relay. Go to the designated waypoint, activate the panel, and watch the fireworks.
Mission accomplished; Infinity is saved.