Twin Suns — Shadow Moses

Before the real Act 4 begins, Snake relives a dream of the original Shadow Moses infiltration — played from the very start of the first Metal Gear Solid. Head to the second floor of the entrance hall and drop into the hangar through the vent. Watch the radar for patrolling guards and security cameras, climb the side stairs, cross the upper catwalk to the left, and drop through the floor vent to close out the dream sequence.

Equip the Solid Eye's night vision and check the map often. A Gekko patrols the ground below partway through — hug the rock to the right and keep an eye on it rather than crossing its path. The facility comes into view once you're across. It's unguarded outside, so take the time to loot the area; inside, Dwarf Gekko patrol, but the same vent from the dream sequence is still there — head up the stairs and through it once you're ready to skip ahead.

The vent leads to new iPod tracks before collapsing partway through — press the prompt to drop down, then turn toward the nearby storeroom for a Ration. Getting to ground level means dealing with Dwarf Gekko: if you have to shoot one, do it fast so the alert doesn't linger and pull in others. Their laser sights make it easy to see exactly where they're looking.

Head left out of the storeroom and down the stairs to reach the ground floor, then right at the first corner to find another floor-level vent. It's mostly a series of left turns from there — don't backtrack outside when it looks like you can. You'll come out near the back of the hangar, with the exit to the canyon through the large door on your right.

A Gekko emerges from the snow as you move forward — easy to avoid if you're watching for it, but don't get complacent. A couple of items sit on either side just before the next large door.

Push forward and duck through the half-open door. Head straight to the locked back door — Otacon directs you to his old office, where the door code is 48273. Take the nearby stairs up and around the corner to the elevator, then head down to the only available floor, B2.

Run straight down the central corridors toward the office — a linear stretch with no resistance. Inside, a cutscene plays; you'll need to manually enter the password on the Mk. II's keypad yourself.

Head back to the elevator. A Gekko shows up partway there — wait for it to turn the first corner, slip down the hallway, and duck under the broken desk on the other side. You can cut through the offices (and grab an M72A3 rocket launcher along the way) to reach the elevator. Check around the corner to make sure the Gekko isn't looking your way before making the final dash — once you're in the elevator, it doesn't matter if it spots you.

Back down the stairs to the rear door. The Mk. III needs a moment to pick the lock, and another Gekko shows up during it — keep it distracted rather than letting it reach the door. If it gets close, shoot its legs with an automatic weapon. Once the Mk. III finishes, push through the door to the exterior.

Rest in the nearby storehouse to top off health and Psyche before the fight starts.

As always, the second phase is a straightforward tranquilizer-and-retreat pattern — aim for her torso and back off whenever she closes in. Defeating her this way rewards Wolf's sidearm and her face camo.

Head down the walkway, hug the wall, and take the alternate path around. Dwarf Gekko patrol here too — get to the lower level again, climb a small ledge to the east, and crouch through a gap in the wall. The next room puts you right by the exit stairs, which are locked; take the elevator on the far side to reach the Foundry instead, staying alert for Dwarf Gekko as you make your way there via the stairs.

The south wing is a narrow corridor; the north section opens into the main floor, with both Dwarf Gekko and full-size Gekko patrolling it. Near the barrels by the conveyor belt, wait for the Dwarfs to look away, then duck under the compressor to cross the belt. A Gekko waits on the far side but is easy to slip past. One more Gekko shows up as you near the exit — shoot its legs, ignore it, and drop down to the exit door.

The first room is tight and full of Dwarf Gekko, making a clean stealth run difficult — and the second door won't open while you're in Alert phase, so either stay hidden the whole way through or clear out every Dwarf in the room if you're spotted. A cutscene follows, leading into the Vamp fight.

Snake and Raiden hold off waves of Suicide Gekko for roughly four and a half to five minutes. The Rail Gun (if you have it) is especially effective against their upper bodies — avoid holding the charge too long between shots. More Gekko arrive in larger numbers as time goes on; Otacon will let you know when their lights stop blinking, meaning they're about to detonate.

Snake pilots Metal Gear REX out of the facility. Gekko attack from every direction, but REX's Gatling gun handles them quickly — tap the fire button instead of holding it down to avoid overheating. REX will take damage, but as long as you keep clearing enemies, its health holds up.