Your name is Fluttershy. You find it helpful to remind yourself of these things. It keeps you from freaking out more than you currently are. After attempting to find your friends via the noble art of cowering under the table for a few hours, you decide to assume that you won't actually have to worry very much about being hurt. The game, or whoever was running it, seemed mean and insensitive, but it also seemed lonely and bored. Or you assume it would be lonely and bored. It probably wouldn't want to kill the three of you at all. At least, not so quickly. At least, you hope so.
Okay, so it's not exactly a bulletproof line of reasoning, but it helps you gather up enough courage to leave the library and try to help your friends. As you approach the door, Rarity-statue slides out of the way. Or floats. It's still extremely unnerving, but you manage to avoid panicking completely. You open the door and step outside. Rarity-statue leaves as well, sliding away towards Carousel Boutique. You see a number of ponies in the street. Or pony-statues, rather.
They all have the same black eyes, as far as you can tell. None of them are currently moving, aside from Rarity-statue. A small bird-statue flies down from a tree branch to greet you. Well, "flies" implies a lot. It would be more accurate to say it floats toward you. You cringe away from it. After bobbing in place a few times, it fly-floats away.
Looking around, you notice that the colors of the world seem slightly muted. You really wish you could just leave, or at least curl up in a corner and hide until Rainbow Dash finds you. But your friends might need your help, so you take a deep breath and start walking. You have no idea how you are supposed to find your friends, but you might as well start by searching the rest of Ponyville.
You try to reattach your library door with magic, but the second you release it it falls back to the ground. You give a huff of frustration and decide to leave it be. You are still leery of the wisps (you've decided to call the balls of light wisps, for the time being), but the notes have made it clear that the game was just messing with you. Maybe. At any rate, the wisps haven't done anything besides float to and fro.
Ponyville seems to be the same as before, minus any lights and inhabitants, excepting the wisps. The ground is also different. The light from the wisps does not illuminate it, but it feels and sounds like marble when you walk upon it. Maybe it is marble? You lower your head and squint at the ground. Nope, nothing. You cast a light spell. You can barely make out some variation in the look of the ground. You raise your head, frowning. You guess it really is just a very dark marble. Very dark and dull. You shrug. This isn't very important at the moment.
You decide to head toward Sugarcube Corner. If anywhere in this creepy game is going to be reassuring, it will be Pinkie Pie's place of work. You hope Rainbow Dash and Fluttershy will feel the same. If you're lucky, you can find each other right away!
Turning a corner, you catch sight of the colorful building. You stop in your tracks. It is very bright and colorful. It looks like it is lit up the same way that your library was. You think it should feel all the more inviting, but for some reason it just makes you feel nervous. You decide to enter anyway.
You realize something is wrong right away. It takes you a second to realize that you can hear something. You find it odd that you hadn't noticed the complete silence before now. It sounds like somepony is walking around upstairs. You stare at the top of the staircase. Eventually, the footsteps stop. After a few more moments, you tear your gaze away and examine the shop. It is surprisingly very empty. The counter and all the shelves are completely bare.
The door to the kitchen has a curtain drawn over it. You walk over and pull the curtain aside before screaming and falling on your rump. The Purple unicorn on the other side also falls backward. Your heart is pounding in your chest. Of course it would be a mirror. You angrily close the curtain. No point in accidentally scaring yourself again. You turn around and feel your heart skip a beat. Pinkie Pie is standing right behind you, smiling.
You gape at her. "P-Pinkie Pie?! What are you doing here? How did you get in the game? Why were you standing right behind me like that, you could have given me a heart attack!"
Pinkie Pie just giggled. "Sorry, Twilight! Oh, you're playing a game? Oh! Oh! Can I play?"
"Pinkie Pie this is serious! I activated some strange artifact and now Rainbow Dash, Fluttershy, and I are trapped in some creepy alternate Ponyville! I have to find them before something bad happens to them!"
"How do you know something bad hasn't already happened to them?" Pinkie Pie started bouncing around the room, still smiling.
"What... Pinkie Pie, aren't you worried about your friends?"
"Well I would be, but you said it's a game right? Besides-" She stop bouncing and slung an arm over your shoulders. She continued in a conspiratorial whisper. "-between you and me, I'm not actually Pinkie Pie." She resumes bouncing. "I mean, I guess I technically am. Or close enough. But Pinkie Pie isn't in the game the way you are. It's probably easiest to think of me as an illusion. I'm supposed to mess with you or something, but you're my friend and I wouldn't want to do that. The game said it was alright if I tried to help you instead. It said something like "oh, that's alright. just you interacting with her at all should mess with her head enough on its own. Go ahead and be friendly if you want." So I did! And then I followed you inside Sugarcube Corner and then you turned around and saw me and then we had this conversation that we just had! Pretty neat, huh?"
You work your jaw, trying to think of how to respond to that. "Okay, so you're part of the game, but you still act like Pinkie Pie and consider me to be your friend?"
You decide you might as well take her word for it. She certainly acts like Pinkie Pie. "Wait, you said you followed me inside? You mean that wasn't you stomping around upstairs?"
"Nope!" She stopped bouncing again and affixed her gaze on you, her face serious. "You know, that's probably not good. You know, the game didn't tell me if you can actually get hurt or not while playing. I mean, it seems like it definitely wants to hurt you emotionally and mentally, but I don't know if it will make an exception for hurting you physically. You should probably run. Like, right now."
The calm way she said it sent ice through your veins. The sound of footsteps return a second later. They aren't as steady and slow as before. It sounds like something is running very quickly. You freeze for a few seconds, yelling in your mind for your legs to listen to you. Pinkie walks to the door and turns once again to face you. "You know, just in case. I have no idea what will happen if it catches you!" She leaves the bakery.
You snap out of it and bolt for the exit. You make it outside but see no sign of Pinkie Pie. You continue running until you are several houses away and turn around, watching the shop. A wisp exits the shop. A moment later, the shop darkens like the surrounding buildings. The wisp meanders across the street and enters another building, which lights up. You get the feeling that the wisp was what was making the noise. Presumably, a building that is lit will have a wisp inside, trying to get you. You hope you don't have to enter any lit buildings any time soon.
You stare at one of your feathers as it floats on the surface of the water. It is probably one of the oddest things you seen. Well, excepting the upside-down body of water in the first place. You pluck the feather off the surface and release it, watching as it falls slowly to the ground. Okay, so it seems like anything inside the water will think up is down as well, but won't once it leaves the water. A sudden shimmering catches your attention. A solid circle of light floats through one of the half-submerged windows. it approaches the spot where the feather was, then remains still. You pick up the feather and stick it to another spot on the surface. The circle of light immediately moves to the feather and encompasses it. The feather suddenly shoots into the ground at high speed, along with several books that happened to be above (below?) the circle at the time. You wince at the sound of books cracking against the wooden floor.
The light wanders out through another window. You get the feeling that it will chase anything that touches the water and shoot it back out. Not exactly a pleasant looking experience. You decide to step out of the library. You are shocked to see a gaping void before you. Peppered about are several island pillars of rock. The library sits upon one such pillar. Above you is an endless expanse of water. Everything is fully lit, as though it were midday, despite the lack of a sun. Rainbow prepared to leap into the air to try flying to another pillar when she noticed a note sitting on the ground in front of her.
There's no way your going to figure this on your own without screwing up badly, so I figured I would be nice and tell you myself. The ocean above your head? You can breathe in that no problem. The vast empty void beneath your feet? You can't breathe in that and you will drown if you stay out of the water. You can fly in the void though, inasmuch as you can fly while suffocating. The only places where you can breathe the air are the islands.
You look back up and stare in shock at the numerous circles of light patrolling the water. This isn't going to be easy.