No matter how engaging the mechanics are, a good video game also needs to have a good story. Without it, you don't have much of a reason to play a game through to the end.

So to keep these endings worthwhile, game developers have devised a number of plot twists. They may not seem like much when taken out of context like this, but in the moment these twists really make these games shine.

Here are the 15 greatest video game plot twists of all time.

Wheatley’s Heel Turn

At the beginning of Portal 2, robotic Wheatley is a charming and bumbling sidekick, complete with an adorable accent.

But when he gets corrupted by too much power, he becomes a worse villain than GLaDOS ever was, and you are eventually forced to exile your former friend to the moon.

Tidus Fades Away

In most games, the main hero beats the bad guy and gets the girl.

But this was impossible in Final Fantasy X because we discover that Tidus is more of a spiritual echo of a long-dead sports star.

And once you conquer Sin, Tidus fades away entirely instead of getting to cuddle Yuna.

Death of Aeris

In Final Fantasy VII, it looked like Aeris (or, if you’d prefer, Aerith) was going to be one of your main characters throughout the entire game.

This made her brutal murder at the hands of Sephiroth particularly shocking to gamers all around the world.

Call of Duty 4: Bombs Away

The Call of Duty series is usually pretty predictable, taking its cues from countless action movies and TV shows of the last few decades.

But Modern Warfare had an unexpected twist: your character actually botches an attempt to stop a nuclear detonation which leads to massive death and worldwide upheaval.

Braid: You’re the Bad Guy

Braid wore its inspiration on its sleeve: the game plays like Super Mario Bros. if our hero had the ability to move time backward and forwards.

Like Mario, Braid's protagonist Tim is trying to find a princess who has been taken by a villain.

Only at the end do we realize Tim is a creepy stalker and the “villain” is a hero who saves the princess from your character.

Resident Evil 4: Not Zombies

The Resident Evil series conditioned players to expect hordes of shambling zombies in every game.

But in Resident Evil 4, the traditional zombies have been replaced by infected villagers.

Not only are they faster than zombies, but these villagers turn into deadly Lovecraftian monsters after taking a bit of damage.

Betrayal in Red Dead Redemption

In the first Red Dead Redemption, it looks like you are going to get a happy ending by uniting protagonist John Marston with his family.

But he's then forced to fight off wave after wave of cops, soldiers, and agents, and he dies soon after escorting his family to safety.

Crono Dies

Chrono Trigger for the SNES is one of the best games of all time, and Crono is one of the most unforgettable protagonists.

That’s why it was so shocking to see him get killed partway through the game by the villainous Lavos.

Even more shocking, you can choose whether to try to save him or finish the game without him.

Female Samus Reveal

Some of the best plot twists go back to the golden age of gaming.

When they first played Metroid, most gamers back in the day assumed our protagonist (whose face and body proportions are hidden by the iconic suit) was a male.

By beating the game, players could see that Samus Aran was a female (and speedier players could even check out her bikini).

Bioshock and Mind Manipulation

In the first Bioshock, you get guidance and instructions from the friendly Atlas, and the instructions always start with the phrase, “Would You Kindly.”

Only by the end of the game do we find out that your character has been brainwashed, Atlas is a baddie, and “would you kindly” is a hypnotic trigger phrase to manipulate everything your character does.

Silent Hill 2: Dealing With Trauma

Silent Hill 2 is a trippy game where your character, James Sunderland, is just trying to meet his wife, Mary.

Soon, he's facing horrific monsters and haunted by a woman who looks a bit too much like his wife.

By the end of the game, we find out James has killed his wife and the entire narrative has been a representation of his trauma and guilt.

Darth Revan Reveal

The Star Wars game Knights of the Old Republic gave us the ultimate franchise plot twist.

You start the game as a powerful Force user with a murky plot who is working with the Jedi and the Republic to fight Darth Malak.

But by the end we find out you were originally Malak’s master, Darth Revan, and your new identity is 100% a result of Jedi brainwashing.

Betrayed By GLaDOS

Portal starts off simply enough, giving you plenty of time to play with the physics-defying powers of the Portal gun.

But you eventually discover that these tests administered by the robotic GLaDOS are designed to kill you, turning the second part of the game into a fight for your life.

Be the Bad Guy in Castlevania: Lords Of Shadow

Usually, the formula for a Castlevania game is simple: you find and kill Dracula.

But in Lords of Shadow, the big Drac is nowhere to be found.

Only in the post-credits scene do we see that your character Gabriel has become Dracula and this was all just a prologue for the series’ greatest villain.

Metal Gear Solid 2: Villain Reveal

Metal Gear Solid 2 is a mixture of amazing gameplay and baffling plot.

Perhaps the strangest thing is the reveal that Raiden’s boss Campbell is actually a creepy Artificial Intelligence that somehow dates back to the founding of the country.

It makes no sense, but we can’t say it wasn’t a surprise.