Welcome! If you guys want to write your own stories like this, go ahead. I don't mind as long as you tell me about them so I can read them. The difficulties are as follows. Cakewalk, Very Easy, Easy, Normal, Medium, Medium-hard, Hard, Very Hard, Insane, Impossible.

Twilight and the real Cadance hurried through the hall, headed straight for the chapel. They burst through the door, and Cadance called out "Wait!"
Proceedings ground to a halt, almost everpony did a double-take at the Cadance Twilight had brought with her.
"Woah, didn't see that coming." Pinkie said, surprised.
"That's an impostor who's been posing as me for the past month." Cadance explained.
"Okay, but how are there two of you?" Rainbow Dash asked.
"She's a changeling. Changelings specialize in disguises. What's more, they feed off love. They take the form of somepony you love, and then gain power feeding off your love for them."
The impostor ground her teeth angrily, before smirking. "Right you are princess, and as queen of the changelings it's up to me to find food for my subjects," the changeling said, after having dramatically revealed her true form rather stupidly in Twilight's opinion. Then again, she couldn't really have managed to fool anyone after Twilight brought the real Cadance to the wedding.
"Shining Armor's protection spell will stop them from ever even reaching us!" Cadance said, faithfully. Twilight was less sure, he didn't look well to be honest with herself.
"Oh, I don't think so, he's under my control, and my army's been chipping away at that barrier around the city for hours, I'd say you've got another five minutes before it disintegrates, Then you'll be at our mercy." the changeling queen said, smirking triumphantly.
"Canterlot is only the first step of course, the rest of Equestria will follow." Her smile turned slightly predatory.
"I won't let that happen," Celestia stepped forward. "You may have prevented Shining Armor from casting his spell, but I will not let you do as you please," she said determinedly.
"Oh? As I recall, you couldn't tell the difference between me and your precious niece, even siding with me over your student. Faithful indeed, she's not even bothered by that. I've never been able to inspire that kind of blind loyalty. I bet she asks how high when you say jump and everything," the changeling mocked.
"I'm sorry about that Twilight," Celestia apologized.
Twilight shrugged. "I didn't have any solid proof of anything and-!" her eyes widened. "Look out!" she pushed the solar monarch out of the way of the changeling queen's attack, only to take it directly in the chest.
Celestia stared, in a mixture of disbelief and horror, at the gaping hole going straight through Twilight's abdomen.
Twilight stared stupidly at the hole. "Huh, I kind of thought that would hurt more." And with that, she toppled over, dead from the fatal wound.
She woke up in a black void. She was standing on something solid that seemed invisible. "Huh? Where am I?" she could see herself just fine, there was just nothing else to see, which didn't make sense. Where was the light coming from?
Suddenly, a strange rectangle popped into existence at her hooves in front of her with the words.

[center][color=#2caf26]'GAME OVER. YOU ARE DEAD.'[/color][/center]

She stared. What the- ? Was this purgatory or something? Or was somepony up there (or possibly down there) playing some kind of joke on her?
A little animation of a grave on a grassy field appeared below the box. She blinked. This was either a very elaborate joke, or her life was some kind of a game. She really hoped it was the former, rather than the latter.

[center][color=#2caf26]'Game Score Compilation:[/color][/center]

[color=#2caf26]The Good:

Watched Summer Sun Celebration and became inspired. +10 points.
Hatched Spike. +100 points.
Passed Entrance Exam. +100 points.
Became Celestia's student. +1000 points.
Befriended Princess Celestia, Princess Luna, Cadance, Shining Armor, Spike, Pinkie Pie, Applejack, Rainbow Dash, Rarity, and Fluttershy. +100 points each times (10). +1000 points.
Used EoH (2) times. +100 points each times (2). +200 points.
Defeated Nightmare Moon. +500 points.
Quelled the Ursa Minor. +500 points.
Sealed Discord. +1000 points.
Restored Discorded friends. +100 points.
Dealt with (49) crises/ friends problems. +20 points each times (49). +980 points.
Timetraveled. +100 points.
Rescued Cadance. +100 points.
Sacrificed yourself for a loved one. +1000 points.
Lived to (16). +160 points.
Subtotal: +6850 points

The Bad:

Didn't Make Friends Until 14. -500 points.
Fell Prey To Discord's Influence. -500 points.
Tried To Make A Friendship Problem. -1000 points.
Got Killed. -500 points.
Subtotal: -2500 points.
6840 points - 2500 points = 4340 points.

Setting Bonuses:

No Tutorial. +1000 points.
No Leveling Up. +5000 points.
No Item Drops. +1000 points.
No Experience Rewards. +1000 points.
No Money Rewards. +1000 points.
No Hints. +1000 points.
No Saving. +5000 points.
Subtotal: 15000 + 4340 = 19340 points.
Penalty For Cakewalk Difficulty. -3000 points.
Total: 16000 points.
Rating: Good Enough.'[/color]

Well, that's not so bad, though she would have liked to know about this sooner. She would likely have given her life choices more thought if she knew her life was in fact a game. Experimentation required that you plan things out.
Once the shock wore off, she started to freak out. Her life was a game. HER LIFE WAS A GAME! Everything she'd ever done was meaningless, she and everpony she'd ever met had no free will, they were just acting out their directives.
Could anypony she'd met even be considered a person? Could she? Well, they were probably about as much people as her, maybe less since she seemed to be the main character. She calmed down a bit. What she'd done had meaning to her and those she'd spent time with, even if maybe they weren't people.

[color=#2caf26]'Every thousand points gets you a point added to your Statistics, though this only applies the first time you play. Statistics affect every facet of, well, everything the player (you) does. Your original Stats were; Str 6, Int 20, Agi 10, Con 10, Will 11, Regen 13, Wis 10, Chr 12, Lck 10. HP 200, MP 330.'[/color]

She noted 11 was where most of the numbers hovered around.

[color=#2caf26]'You're new Stats, however, are; Str 22, Int 36, Agi 26, Con 26, Will 27, Regen 29, Wis 26, Chr 28, Lck 26. HP 360, MP 538.
Now for an explanation of what each Stat represents. Unless specified otherwise, each pony race has an average of 10 in each Stat.
Str (Strength) affects physical strength, stamina, and adds a point to the damage dealt by physical attacks per point. Earth ponies have an average of 15.
Int (Intellect) affects magical power and control, memory, learning ability, logical problem solving, and, of course, your intelligence. It adds 10 MP to your pool per point, and raises magical damage by 1 point per point. Unicorns have an average Int of 15.
Agi (Agility) affects speed, reflexes, ability to dodge, and flexibility. Pegasi have an average Agi of 15.
Con (Constitution) affects tolerance for pain, overall toughness, and resistance to poison and disease. Each point in Con adds 10 HP to your pool and subtracts one from damage dealt to you.
Will (Willpower) affects self-control, and your capacity/resistance to manipulation and mind control.
Regen (Regeneration) affects the rate at which you heal and your magic recovers. Each point translates to a point restored over a minute.
Wis (Wisdom) affects magic and intuition. It allows you to find the best solution rather than just [i]a[/i] solution. It adds 3 MP to your pool per point.
Chr (Charisma) affects others impression of you, their willingness to follow you as a leader, and the ease with which you make and keep friends.
Lck (Luck) affects anything and everything you do, but especially improvisation and games of chance (ie: chess is less affected than a game of rock-paper-scissors).
HP (Hit Points) how much punishment you can take without dying. In addition to the boost from Con, you gain 10 points from leveling up and from the collectible stars scattered across the game's universe, and have a base 100 points.
MP (Magic Points) these are expended in order to use magic, but some physical moves can require MP as well. Apart from Int and Wis, you gain 10 points from leveling up, and the collectible stars, and you have 100 base points.
Each Stat affects several things, but many have minor bonuses to what is normally another Stat's jurisdiction, Lck is a prime example, as it provides a small boost to everything from strength to charisma.'[/color]

Well, she should do much better this time, clearly she wouldn't have gotten a boost to her Stats if she wasn't going to be able to try again. As if reading her mind, the game continued.

[color=#2caf26]'Don't assume that Stats are a perfect indicator of an enemy's strength or your own. Skills can make a seemingly weak opponent into a powerful enemy.
You have three skills available.
Efficient Spellcaster: 0/5. Each point in this skill reduces MP costs by 5%.
Combat: 0/1000. This skill affects your overall combat ability. At 0/1000, your technique is sloppy, and you barely know which end of the weapon to point at an enemy.'

That was kind of insulting, but it was 0/1000.

'Resilience: 0/1000. This skill reduces incoming damage, a high enough Resilience can even completely absorb damage, though don't expect this with even the weakest of monsters until you reach 25/1000. At 0/1000, you're resistance to damage is almost non-existent. You currently have 22 Stat and Skill points to spend, 6 are free, and 16 from the +16 for getting a score of 16,000 points. Spend them wisely, once spent, they can never be recovered.'[/color]

After looking over her Stats, she decided to save her points until she knew what she'd have trouble with. Her Skills however, she'd put points in.
She got Efficient Spellcaster up to 5/5, and Combat and Resilience up to 8/1000, leaving a single point left unspent. This unlocked two new skills.

[color=#2caf26]'Positive Magic: 0/1000. Grants a deeper understanding of positive magic, the higher the level, the more easily you learn spells tied to positive magic. Negative Magic: 0/1000. Grants a deeper understanding of negative magic, the higher the level, the more easily you learn spells tied to negative magic.'[/color]

She put a point in Positive Magic, hoping to ease her learning of new spells in the future.
Four pieces of white words appeared as the Game Over block and animation disappeared. They said, New Game, Continue, Options, and Quit.
Continue was slightly greyed-out, but the rest were solid white.

[color=#2caf26]'New Game begins a new game, which usually starts at birth. Levels, Skills, and Stats carry over through all playthroughs, and this is true whether you are merely switching between them.
Continue lets you continue from a saved file, but you cannot because you didn't save your game.'[/color]

Logically she'd been at least somewhat aware that she'd have to start completely from scratch, but that one sentence made it sink in, and she instantly became depressed.

[color=#2caf26]'Options lets you change the game mechanics and difficulty.'
'Quit means true, final, death.'[/color]

She took in a deep breath and sighed. Well, she might as well go along with it. She first selected Settings, and looked them over.

[color=#2caf26]'Tutorial: Off. Leveling: Disabled. Item Drops: Disabled. Exp Rewards: Disabled. Money Rewards: Disabled. Hints: Disabled. Saving: Disabled. Difficulty: Cakewalk. HP/MP bars invisible.' [/color]

She raised an eyebrow. With the way this was set, you'd think someone was trying to keep her from ever finding out her life was a game. Well, she couldn't really do anything about it, could she? Besides, she was not [b]looking[/b] for problems with a second chance.
She changed them to her liking.

[color=#2caf26]'Tutorial: On. Leveling: Enabled. Item Drops: Enabled. Exp Rewards: Enabled. Money Rewards: Enabled. Hints: Enabled. Saving: Enabled. Difficulty: Cakewalk. HP/MP bar visible.'[/color]

She next selected New Game, but a box with text appeared in front of her.

[color=#2caf26]'Alert! You haven't updated your game in 16 years. Updates are meant to make the game better, fixing bugs and adding new content.' [/color]

She selected Yes, and the void around her lurched.

[color=#2caf26]'Cheats feature available. Cheats change the way the game behaves, but it requires that you collect golden stars of magic, otherwise you can't use any of the cheats.' [/color]

She found herself staring at a disorganized field of statues of her, albeit sometimes as a different species. There were three main categories however. The smallest group was painted, and looked like they could start moving at any time. The largest group was simply grey, if well-crafted, statues of her. The last group were covered in cloaks, but presumably were of her.
She noticed that the statues were completely disorganized.
"I wonder if I can sort this place out a bit," she mused, only for the statues to do so themselves, and found herself in front of the colored versions.
The first was identical to her, down to even the most minute detail.

[color=#2caf26]'Basic Twilight.'[/color] a pop-up read. [color=#2caf26]'The original version of Twilight, upon which even the most twisted avatar is at least loosely based. An all-rounder who is not magnificent at any one thing, but not terrible at anything either. This avatar is always unlocked.'[/color]

Well, that was her from the first time, obviously.
The next wore glasses and appeared to be reading a book.

[color=#2caf26]'Genius Twilight. This version of Twilight has an IQ of 350. Twilight's always been intelligent on the super-genius level. She can decipher any puzzle or complete any intellectual challenge. Friendship has never really interested her, she considered it a waste of time she could spend studying. So she's socially inept to an almost unbelievable degree. Unlocked by studying for 1000+ hours.'[/color]

That was interesting, she could probably switch between them. She could use that to study with Genius something that was troubling her in another of these.
The next was a strange biped in a light blue shirt, dark blue skirt embroidered with her cutie mark, and a pair of white boots, she'd say some kind of primate, surrounded by semi-translucent blades, and had a cold expression.

[color=#2caf26]'Warmage Twilight. This Twilight is the younger sister of Noctis, a prince in an alternate Equestria where neither Celestia nor Luna exist and the forces of nature are controlled by 6 Crystals spread between three kingdoms.
Equestria posses the Solar, Lunar, Water, and Earth Crystals. The Tauros States posses the Fire Crystal, while the Gryphon Kingdom has the Wind Crystal. Tensions between the three have been rising, mainly because the Gryphon and Minotaur nations war with each other almost constantly, while making demands of Equestria ranging from aid to handing over one of their Crystals. Requires the Swordsmare Avatar to be unlocked.'[/color]

Okay, she'd leave that one for now. Not a fan of war.
The next had a pair of swords strapped to her back.

[color=#2caf26]'Swordsmare Twilight. This version is as talented with blades as with magic. She joined the Royal Guard like her brother, and when she proved talented in both combat and magic, was made a member of Celestia's personal guard. Unlocked by having a family member in the royal guard as a ranked officer.'[/color]

Huh, that might be interesting just to go through.
The next had a sly, Cheshire Cat-like, grin.

[color=#2caf26]'Politically Savvy Twilight. After noticing an alarming tendency of nobles trying to either corrupt or intimidate her student into subservience in hopes of gaining some influence on Celestia herself, which Twilight was resisting remarkably well, she began to teach her student politics.
Having been taught by someone with centuries of experience, she is very skilled. However, she remains loyal to her mentor, as nearly every Avatar does. She is, unfortunately, somewhat mistrustful of others after how the nobles tried to use her to get to her mentor. Unlocked by becoming Celestia's student.'[/color]

Yeah, the first part had kind of happened already.
The next was once again bipedal, and was halfway through drawing a runic circle of some kind.

[color=#2caf26]'Alchemist Twilight. This version is from Amestris, a country in a world where alchemical transmutation is possible. Alchemy is the science of analyzing an object, breaking it down into it's basic components, and restructuring it. It is governed by the law of equivalent exchange, which states that in order to obtain, something of equal or greater value must be lost.
She is an ally of the Elric brothers against the Homunculi. Requires Genius Twilight and having used the Elements of Harmony at least once to unlock.'[/color]

Now that sounded interesting. She'd definitely want to see what that was about, since it sounded like an actual other world.
The next was another biped, this time in a black robe with an insanely long katana and a mask formed from dark energy on her face. The mask radiated evil.

[color=#2caf26]'Twilight Kurosaki. This version is from a planet called Earth, specifically Karakura Town. She is the second eldest of the Kurosaki children. She can see spirits like her elder brother, but this could attract unwanted attention in the future. Unlocked by being killed, and requires Swordsmare Twilight.'[/color]

Odd, this world sounded very different somehow. Another candidate for playing through?
The next was an alicorn (combination of earth pony, pegasi, and unicorn) filly.

[color=#2caf26]'Alicorn Twilight 1. This version hatches Spike without the aid of the Sonic Rainboom, and becomes an alicorn in the process. Unlocked by hatching Spike, becoming Celestia's student, and using the Elements of Harmony at least once.'[/color]

Yeah, that was a bit overwhelming. She didn't really feel comfortable with this version. It felt blasphemous.
The next was a biped that had a strange key-shaped sword. The teeth were formed from the star of magic, the shaft was dark purple, the guard was golden and circular, the handle was white, and the keychain was the stone orb her element had been inside when she first saw it.

[color=#2caf26]'Twilight the Keybearer. Aprrenticed to Master Yen Sid, like King Mickey, she later joins Sora on his quest to defeat Organization XIII at her master's behest. Unlike most Avatars, she has some basic understanding of the importance of friends. Unlocked by using the Elements of Harmony, writing at least 10 friendship reports, and requires Swordsmare Twilight.'[/color]

Well, 'the Keybearer' that sounded destiny-ish. Another candidate.
The next of the colored ones looked like Basic, but had a calm, determined expression.

[color=#2caf26]'Enhanced Twilight. Several alicorn genes make this an improved version of Basic, though still an all-rounder. Unlocked by playing as Basic Twilight at least once. Adds 100 HP/MP.'[/color]

Huh, that sounded great! Essentially a better her. She was doing this one first.
The next was a pegasus instead of a unicorn.

[color=#2caf26]'Pegasus Twilight. Their filly being a pegasus was not that surprising to her parent since they had pegasi genes in the family. This version has as much talent for weather manipulation as Rainbow Dash has for flying. Befriend at least two pegasi to unlock.'[/color]

That made sense, her talent for unicorn magic translated to skill in utilizing the more active aspects of pegasi magic.
The last colored one was an earth pony.

[color=#2caf26]'Earth Pony Twilight. The fact that their filly was an earth pony was the cause of much sneering among the other nobles towards the Sparkles. However, she excelled at earth pony magic. She was strong enough to uproot a small tree from an early age, then cause an instant replacement to grow. Unlocked by befriending at least two earth ponies.'[/color]

Once again, her talent for magic had transferred over.
The grey ones were not yet unlocked for use, as it turned out, and when she tried to touch one of the cloaked ones, a blast of energy shot by where her head had been a moment before.
"Don't touch... right, got it," she said, more than a little freaked out.
She decided to start with Enhanced. It was close to Basic in terms of background, and she'd take any advantage she could get. Her HP would be 460, and her MP would be 638.
After she selected it, she found herself waking up to her old room. She took a look at the nearest calendar. It was the day after her fourth birthday. Huh, old enough to be able to move around freely, but not old enough to have her life set in stone. Convenient.