Metal Gear Solid: Peace Walker/Pupa Battle

The nuclear payload you have been chasing has been moved far away to an unknown location. The enemy has deployed a high-tech unmanned weapon - the Pupa - to kill you. A local scientist is offering you advice for dealing with the Pupa over the loud speaker.
 * Destroy Pupa with the help of the scientist.

Mission Prep
Pupa is one of the second flavor of boss in this game: the AI Weapon. AI Weapon battles have no stealth element; they always know where you are. Since camouflage is not a consideration in this mission, you may as well go Naked to maximize your speed, weapon damage, and Heroism yield. An aggressive loadout would consist of the ★1 RPG-2 and the ★1 LAW as your two Primary Weapons, with the ★1 Supply Marker as your secondary weapon. A conservative loadout would swap the ★1 LAW for the ★1 M60 machine gun. Your top item should be the ★1 Ration while the ★1 Mate should be brought to restore your Psyche, as all AI Weapons have attacks that damage Psyche.

Destroy the Pupa
At the beginning of the battle, Pupa will speed up and travel along the curved walls. It will move to fast for rocket launchers at this time, so focus on preparation. On the edges of Crater Base are three nooks that open into tunnels. You cannot access the tunnels, but the nooks are good places to retreat to when you need to reload, heal, or call in a resupply. You will start just outside one of these nooks. Run in while Pupa starts moving around the curved wall. Immediately equip the ★1 Supply Marker and hold down and press  to place the Marker at your feet. Do so at a place within the nook, but at some distance from the walls. While the Supply Marker is equipped, press again to confirm the supply drop at the location of the marker. Go ahead and do it now, but don't pick up anything yet.

As Pupa moves around the arena, its dorsal machine guns will take potshots at you. It's okay to tank them; damage doesn't seem to affect your grade. Going out into the arena seems to goad Pupa into coming down for stronger attacks. Doing so causes it to stop and makes it vulnerable to rocket launchers. The scientist will advise you to aim for the cylindrical AI Pod, and that is exactly where you should direct your attacks. Try and zig-zag your movement as you reload after your shots. If time ever becomes a factor, swap to the LAW in lieu of reloading.

When Pupa stops on level ground, it will prepare its shock attack. The shock cannon beneath its AI Pod will move, then stop before firing, so try to keep an eye on it. The shock cannon only has a 45-degree range of motion at Pupa's front, so you can try to attack from the side. The dorsal machine guns will continue to take potshots between shots of the shock cannon. Getting hit by the shock cannon will briefly paralyze you and damage your Psyche. If your Psyche empties to zero, you will have to waggle until your Psyche is full to get back up. Try to recover Psyche by using Mate whenever you can.

Pupa will also fire its boosters for a ram attack that will either get it back up on the wall or into one of the tunnels in the three nooks. Either way, watch to see if Pupa is aligned with you when it announces that it will fire its boosters. If it is going to collide with you, press and hold to lie flat and allow Pupa to safely pass over you.

While in the tunnels, Pupa is invulnerable. If you have headphones or surround sound, you will be able to hear Pupa's "singing" giving away its position and be able to discern where it will emerge. If it will emerge from the tunnel you're in, either run into the open central area, or hold down until it passes over you.

When you can't reliably attack Pupa with rocket launchers - either when it is on the wall or in the tunnels - that is the time to reload your weapons, fill your Life and Psyche, collect from your supply drops, or call in new ones.

When Pupa's Life starts to get low, its attacks will change. Instead of a single shot from the shock cannon, it will fire three in rapid succession. Don't let this hit you.

It also has a desperation move in which it will deploy many hockey-puck shaped objects at random locations. The scientist will describe them as "lightning rods." Sometime later, Pupa will use them to direct a chain-lightning attack all over the arena; if a lightning rod is near you, you'll get hit, so try to destroy them with your machine gun if that happens. If you didn't bring it, consider sacrificing a missile, or finding a new position without any lightning rods around. Once Pupa completes this attack, the rods will be destroyed.

Access the AI Pod
Once Pupa's Life reaches zero, it will become immobile and a Life bar for the AI Pod will appear in a similar manner to a Captain's life bar on vehicle boss fights. Simply fire another rocket to completely deplete the Life bar. Once the Life bar of the AI Pod is depleted, you may approach the pod, and enter it by pressing.

If you're playing CO-OPs, only one player may enter the AI Pod. The rest will need to continue fighting the Pupa with their buddy inside the Pod. While within the AI Pod, a series of memory boards will be displayed. There are four columns: A, B, C, and D, with a number of colored icons representing the boards. You have a countdown indicating whent the AI Pod will eject and escape. Starting at column A, use / to highlight a colored icon and press to pull it out. Try to pull out all the colored icons before moving onto another column. Use / to highlight an icon on another column. Selecting another column will cause your character to move around the interior of the pod to the corresponding column, costing valuable time to remove the memory boards. Acquiring memory boards is important to the process of building MSF's own AI Weapon.

The red memory boards cannot be removed. Black memory boards can be dislodged by the attacks of other players, allowing you to pull them out once they become dislodged. This only works in CO-OPs, however.

Once the timer reaches zero, you will be ejected from the AI Pod, which itself will detach from the weapon and rocket off to places unknown. The destroyed husk of the weapon will remain in the arena.

Completion
With the Pupa destroyed, the scientist - Dr. Huey Emmerich - will reveal and introduce himself. He will join MSF as S-Ranked R&D staff. Putting him in the R&D team will trigger the Metal Gear option to be unlocked when you complete the next mission.

This is the end of the story segment of Chapter 1. Completing this mission will unlock the Extra Ops [007] Marksmanship Challenge and [069] Armored Vehicle Battle: BTR-60 PA.

Chapter Denouement
The nuclear material you've been chasing is meant to arm a new automated fail-deadly weapon called Peace Walker, a nuclear weapons platform controlled by advanced AI. The philosophy behind Peace Walker is that nuclear deterrence is based on the fact that if the Americans launch even one nuclear weapon, the Soviets will retaliate with all of their nuclear weapons and vice-versa. Contrary to the accepted theory of deterrence is that during the Cuban Missile Crisis a Soviet submarine commander refused to launch when ordered - an act that arguably saved the world. Hot Coldman believes that without a guaranteed retaliation, one without human hesitation or sentimentality, the long peace brought by nuclear deterrence is itself not guaranteed.

Peace Walker has the intelligence to judge where and how it must retaliate but lacks the human attachment to the world. With AI controlling the launch, retaliation is guaranteed; any nuclear power that strikes against a target that will retaliate to any and all acts of nuclear aggression without regard to ideology or state is effectively destroying themselves. However, Coldman feels the need to test his theory by having Peace Walker actually launch its payload.

The only thing stopping this is the fact that Peace Walker's electronic brain is yet to be completed. Huey will provide the intel needed to track down the laboratory of Dr. Strangelove and stop the completion of Peace Walker.