And because it took such a ridiculous amount of time to update that with no excuse, here’s an alternate update. This one is under the assumption things went much differently then they have so far and you’re controlling “Amy” in the same situation.

Keeping the door slightly ajar, you stealthily creep across the room with as much swagger as you can muster. As you reach the far end of the room you try to picture Amy. Spry, athletic build not uncharacteristic of a pegasus. Lot of heart; lot of fire. But you can’t help but feel she would probably wind up cheating on you. N-not that you were thinking of going out with her or anything!
Now that you’re inside, you see there are two more hallways; one to either side of you. You can hear multiple sets of hoof steps coming from the hallway that shadow slipped behind.
In a moment of clarity you’ve lacked as of late, you look around the room for architectural signs. Regrettably, just about everything is gone. You can see signs on the floor where furniture once sat, a few pieces of splintered wood and dirt, but little else. In addition to the light from outside, this building seems to contain a dim light source that makes seeing possible without any aid, but you can’t make out from where it originates.
Looking up, you can see the floor above you, complete with railings still intact. They appear to be made of a metal, but it’s hard to tell from this distance. Everything you can see has a black/gray dingy coating to it. There’s also a… fog of some kind. It seems to be getting worse and coming from the door being open.
Continuing with this new-found focus, you listen carefully to the hoof-steps. It sounds like three different sets. Working off that alone, chances are the shadow you saw pass around the corner was just your friends.
That thought, even if wrong, relieves you enough for the moment to realize it’s strangely warm in here.

You slowly open the door, expecting it to creek loudly like in the movies. It’s quiet, though.

You peek your head inside first and look around. The foyer is somewhat smaller than you’d expect compared to the hall you first entered from. There’s a hallway straight ahead and the first thing that grabs your attention is the shadow pass around the corner, and out of view.
The unease that should be setting in is replaced by confusion at how in Equestria you’re going to tell the others that you’ve fallen for a giant shadow pony.

While the giant is still disabled, you run out into the snow and head for the semi-circular building. You glance back one last time at the giant and sigh. Sorry…
Upon arrival, you find what appears to be 4 or 5 sets of tracks in the snow heading north-east. That electrical thing must have followed them! You race after the tracks, but find they reduce to only a clear 3 after about halfway. That would mean the electric shadow gave up and went back to the semi-circular building. You continue onward, following the tracks toward the building with the high roof.
Puzzle complete!
After reaching the building you find it to be much larger than any of the others. It’s base alone stands taller than the long building to the south of you. The roof only adds even more height.
The 3 tracks lead right up to the doorway, so your friends must be inside.

You draw another arrow, but pause for a moment.
The first arrow you fired did no damage; it just made the shadow angry. Even a shot to the face has only seemed to stun it. What good would firing several more do but waste time?

A violent streak takes hold of you. You wrap the blanket back around you and lower the hood to half cover your eyes. After drawing and stringing another arrow with your mouth, you slowly progress toward the edge of the doorway.

You lift your head until you can see the edge of the shadow’s eyes, then close your own, aim slightly higher, and fire.
The following sound is so incredibly loud and terrifying you fall backwards! Inspecting the situation reveals the giant with its head lowered and one hoof covering its face, stomping with its hindlegs Chances are you probably missed your mark, but you must have hit something!
Quickly now! While it’s recoiling!

Without much direction, you remove your blanket and cover your head up with it before looking at the shadow again. Nothing happens, but then again the weave is thick enough that you can’t see through it. Evidently, you have to make eye contact with the giant for it to blind you. You add that to the knowledge that it doesn’t have to be consciously aware of you to use the power; it’s automatic.
You then whip the blanket out of the doorway, to which the giant immediately lifts and steps on it. You quickly try to tug at the blanket, but it doesn’t budge. Waiting a few seconds, the giant lifts its hoof again and you retrieve the blanket unharmed. The blanket might act as a physical barrier if the giant’s body is somehow harmful to touch, but using it as a shield seems impossible with out further direction.
You draw your multitool and inspect it. Small and large knife, bunch of screwdrivers, can and bottle opener, corkscrew, scissors, a few different files of varying coarseness, tiny ruler, reamer, magnifying glass, two kinds of saws, wire stripper, pliers, chisel, tweezers, toothpick you’ve never used as you question its sterility, some… thing with a hole in it for sewing, and a few other things you don’t rightly know the use for, the least of which being some kind of hook. Probably should have picked up the manual from your house while you were in town.
Oh hey! A ball-point pin! Forgot it had one of these!

You return to the doorway that leads into the boxed canyon. The shadow is still there and it doesn’t look like it’s going to give up and go away anytime soon. Being that it’s staring at the doorway, there’s absolutely no way to sneak past. Stupid giant stallion and his stupid… muscular body… Suddenly the shadows on its body seem to almost ripple with intense force. You place a hoof to your face and feel it getting warm. You steal a glance from inside the doorway at the shadow’s face and catch its vortex-like eyes. Instantly your vision darkens to an almost complete black before you pull your head back inside and gasp in fear, waiting for your vision to return.
Nope nope nope nope nope. What were you thinking?! Not gonna happen. Ever. Never ever ever.
———————
This is a puzzle-type situation. Eventually the shadow will give up and go away, but quite a bit of time will pass before then. Players can either continue to try and figure out how to proceed faster (or any number of other things), or vote to wait it out.

You edge close to the doorway and look outside to try and spy any sign of your friends. Unfortunately the blizzard is much too thick and obscures any detail you might be looking for, like hoofprints in the snow. If you’d had the Binoculars you might be able to see something definitive, but if you recall right, Twist has them.
Other than that, everything outside appears as it did before. Ignoring the large shadow staring daggers at you, that is. But you’re careful not to meet its gaze again.
You backtrack along what is most certainly, and without a doubt, a dark tunnel. Because there are no other paths leading off of it. And it’s poorly lit.
You climb the stairs at the end of the tunnel and come back out at the armory. Since you’re already here, you take his opportunity to grab 2 more Arrows, bringing your total back up to 20. From there you head back into the grand hall with the large table and the metal chairs. You look around but the only exit from here other than the armory, is back outside where you first entered from. And where this all began.
Well…Exit found.
From here you can even see the still-open gate from where you first used the key. Looking into the brightness outside, where the sun isn’t obscured by the snowfall, you check the time on your nifty Multitool to find only an hour has passed. It’s currently 9 AM.

You take stock in your current situation, to try and clear your mind. You aren’t necessarily trapped, just separated from your friends. Though it’s dark, there doesn’t appear to be any clear danger where you’re standing.
You still have your Cloak-Style Blanket, which appears undamaged. After firing two Arrows, you still have 18 left plus the Bow. You have your Food and Water supply along with your Multitool and the Rope. You’ve Lost your Clawed Gauntlet in the fight; if not permanently than at least for the moment.
Now that you’ve calmed down, you can’t help but look down at your chest. You could have sworn you saw something being pulled out while you were pinned against the wall. Then seeping back in once you were rescued, but there’s no visible marking. On the other hoof, you now have a very unsightly scorch mark on your right shoulder. But with any luck that’ll heal over time.
The Giant Shadow has stopped striking the doorway, but it’s still waiting just outside.

Once you manage to shake the notion of a shotgun wedding, you turn around and run as fast as your little pony legs can carry you! Looking back you see exactly what you expected to see; even your fastest can’t outpace the grand stride of the giant’s booming hooffalls.
Having no idea where to turn with it gaining, you make for the awning and pass through back into the dark tunnel. Corridor. Whatever!
You travel partway into the darkness before turning around and hearing pounding on the stone walls. But oddly enough, that’s all you hear. No crashing of stone, no cave in; just a dull pounding.
Curiosity gets the better of you and you approach the opening back out into the… courtyard? Are we going to call the massive space a courtyard now? Focus!
The giant has its knees bent and is standing under the awning kicking at the doorway you’re on the other side of. But for some reason, its attempts are futile. No matter how many times, or how hard it strikes, it seems incapable of causing any structural damage. Not even a chip!
Looking back out into the courtyard in between swings, you notice that the giant doesn’t leave any hoofprints in the snow either. You cautiously cover your hoof with your blanket and stretch out to touch the shadow, or see if it can touch you.
It certainly can touch you, and the force is much more powerful than you thought. After you pick yourself up off the floor, you note these discoveries in your head. For the moment, though, you’re unable to regroup with your friends, or even find out if they’re alright!

Your compassion takes over, even through the pain you still feel, and you worry about the electrical shadow as well as Princess, Amy, and Twist (though in your mind you miscounted somewhere when you thought three).
You draw your bow string back and let fly an arrow toward the giant. You really need practice; you couldn’t hit the broad side of a barn. Fortunately, the giant is bigger than a barn and you strike it in the hoof. It pulls its leg back in pain, before seeing where the shot came from.
You don’t have much time to react, the giant shadow is now headed toward you.

You lose the next second or so and stumble awkwardly out into the snow. You become aware of the rhythmic boom of the Giant’s hooffalls, only they’re a little faster, and much louder. Looking up you find that it’s much closer and headed straight for you!
Slipping a few times, you struggle to run as fast as you can toward the hopeful safety of the awning and beyond. But when you look back, the Giant doesn’t seem to be coming toward you anymore. It’s headed for the building your friends are still in. If they come out, that shadow could crush them; its massive size making it impossible to outrun. Alternately, if they stay inside, surely that electrical monster would destroy them.
You still have your bow, 19 arrows, and a sizable lead on the Giant from this position. No matter what decision you make, somepony’s life is going to be put in danger.

You scream in shock! This does little to reassure your allies, but you couldn’t help yourself.
Yelling out at the shadow to stop, that it might hurt somepony, does little to slow its approach. It either doesn’t understand, or you’re just mirroring its intention.
Fight or flight instincts kick in something fierce and you rush ahead, gauntlet raised, shouting out an old and tired meme. You nearly tumble forward when your weapon is wretched from your grasp and attached harmlessly to the shadow’s chest. Your vision flashes again and before you can recover, everything becomes unbearably loud and you feel a horrible shocking pain followed by a powerful blow across your head. Before you can even move you feel yourself lifted off the ground and slammed into a wall. Something presses strongly against your throat and you force your eyes open. Everything is blurry, but you can see the monster’s electrical eyes through your own tears. The shadow has you pinned against the wall with one hoof and the electricity surging through you is so painful it’s paralyzing. You’re rapidly losing consciousness… and something else. Something feels loose in your chest, and you can almost feel it leaking through your skin.
Just when you think you can’t hold on anymore, you’re jerked violently to the right and feel yourself drop to the ground gasping for air. The noise has subsided into a ringing and the electrical pain into a strong tingling feeling on your right side. Through blurred eyes, you could swear you saw something seep back into your chest. Somepony helps you to your feet and pushes you away from the noise and the tingling.
You lose the next few seconds. The next thing you know, Princess is holding your face up to hers with her forehooves and screaming at you to run. That it’s after you, not them.
You’re still in a lot of pain, your breathing is labored, and the edges of your vision are still blurry.