|2||Destroyed Sahelanthropus's head.||Optional|
|3||Successfully hit the floating boy with an attack.||Optional|
Are you ready for the final mission? As you might expect, you're going to be fighting the Metal Gear Sahelanthropus here. The best weapons to bring along are those that cause a lot of explosions. You will want both a grenade launcher and a rocket launcher in this battle, as well as the Battle Dress armor to help absorb any attacks you might receive.
Your support chopper will be there throughout the fight, automatically sending supply drops and even helping out in the battle against the giant machine itself. For attacks, the boss will almost always start by drawing a whip-like weapon from its waist and slamming it onto the ground, causing huge rock-like protrusions to erupt, acting similar to the ones that the Armored Skulls used.
These ones will go in a straight line, but it has two more attacks that are similar. If you see the whip become stiff, then the boss will stab it into the ground, either causing the rocks to come up where you're located or to surround you. If it's the latter, then you want to quickly switch to your grenade launcher and shoot one so you can exit this circle. The boss can deploy a red mist, covering the whole area, which does nothing but reduce your visibility; equip your night-vision goggles to counteract this.
It can also shoot at you with its machine gun, as well as charge straight towards you. If you get too close to it, the boss also has a flamethrower attack. Sahelanthropus also has two missile attacks it uses, one it shoots from the front which has a slight homing ability (should you be in front of it) and another set that are large. It will shoot these large ones into the air, where they sit a few seconds before crashing down on your last position.
For the first portion of the battle, the idea is to keep running and moving, even if it's just in a big circle. This should make it so a majority of the boss's attacks will likely miss you. You will be using the rocket launcher for a large portion of the fight, as it does a lot more damage than the grenade launcher. You should receive a supply drop whenever you run out of ammo for the rocket launcher, so keep an eye out for that.
It seems there is a single moment that your attacks do more damage than usual to the Metal Gear. As it attacks, you will notice some vents open up just underneath its head and that's where you want to hit the beast whenever you have the opportunity. There are a couple of instances in the battle where Sahelanthropus will do a few new attacks.
The first instance is after the boss has between 75% to 50% health left, where it will shoot some missiles at your support helicopter. You want to shoot these, or else the chopper will be struck and destroyed, with you losing a good chunk of Heroism points in the process. The next attack happens at around 25% to 50% health remaining. Sahelanthropus will jump onto the rocks and begin firing laser beams. If it knows your position, then it will direct these at you, but it will fire them randomly if not.
There is a spot where you can hide behind a rock, pretty much negating the entirety of the attack, since it doesn't go through terrain, thankfully. The final attack happens when it's at low health. It will leap towards you, with the game slowing down similar to Reflex Mode. You will see the floating boy (the one with red hair you've seen throughout the game) appear in front of it. Switch to any weapon, preferably not your rocket launcher, and shoot him to incapacitate Sahelanthropus for a few seconds.
This is an excellent time to shoot and damage the head, hopefully destroying it for the mission task (shooting the floating boy will also complete a mission task). It appears that Sahelanthropus will deliver a very devastating attack if you don't shoot the floating boy in time, possibly killing you in one hit in the process. Once you've depleted the health bar at the top of the screen, sit back and enjoy the cutscenes and ending.
Warning: During the ending, there is one part where you have the choice to either shoot someone or not. You can simply wait it out, similar to the choice with Quiet during Mission 11.
Complete "SAHELANTHROPUS" mission.