Fix The Ending: Mass Effect 3

Mass Effect 3

The ending, done right

Warning: spoilers abound. DO NOT READ THIS UNLESS YOU HAVE COMPLETED MASS EFFECT 3, OR ARE WILLING TO LEARN THE LARGEST SECRETS ABOUT THE GAME!

Note: I played through as a FemShep, so I'll be referring to Shepard as “She.”

Note 2: I won't discuss the curious changes made in the plot between games, as a result of changing writing teams. That's a subject for other people, or another day.

I recently finished my first play through Mass Effect 3, the end of Bioware's Sci-Fi RPG epic. And I have to say, well done, Bioware. The game was exquisite; it did everything well that the first and second games did well, expanded on the best mechanics, eliminated the worst, and had some of the best levels I've ever played. The moments at the end of the Tuchanka and Rannoch priority missions were profound, touching, and inspiring. I even had to leave my computer for 15 minutes to think when presented with the tiniest choice that touched me on a deep level: how to record myself in Liara's history box.

But there is one glaring, major problem with the game. It has nothing to do with minor bugs (my friend has managed to get out of the Citadel Presidium's structure and take some interesting screenshots) or with minor imbalances (how on earth is a Vanguard supposed to deal with Turret/Engineer combos?).

The final level and ending choice/cutscene of Mass Effect 3 were the worst made decisions since the production schedule of Dragon Age 2. The last battle is unsatisfying, the Catalyst is Deus Ex Machina, the choice is nearly meaningless, and there is no “Fifth Act” to the dramatic structure. No Dénouement. So let's examine these three problems.

Climactic Proportions: Priority: Earth

After taking down Cerberus' main facility, killing Kai Leng (who I wish were more prominent in the game, and better fleshed out), and learning that the Illusive Man has warned the Reapers of your plans with the Crucible and that the Catalyst (AKA the Citadel) is now being held by Earth, you rally all the troops you've assembled, all the fleets, and every character still alive and on the side of Organics, and charge through the Sol Relay.

This triggers a cutscene which is, by all rights, incredible. I was nearly completely Paragon through all three games, with the exception of sacrificing the Council in ME1, so I got to see the combined fleets of Earth, the Asari armada, the Turian navy, and the whole of the Quarian Flotilla, lined up and prepared to battle the endless force that was the Reapers. I got tingles. I got the sickest nerd chills. But there was one major problem. After seeing this incredible battle begin, you then leave and go to the ground.

Now, I understand that Mass Effect 3 is ultimately a game about Shepard, not about the fleets, but almost the whole game was centered on Shepard gaining these Allies in preparation to retake Earth. The most fundamental principle of Video Game Narrative is this: Show, don't Tell; Play, don't Show. However, this battle consists entirely of Show. While a huge battle, the proportions of which have not been seen in hundreds of millenia, rages in the skies above our ravaged home, Shepard and his crew are in a shuttle flying by. Now, I could excuse this in my mind, but Bioware has shown that its Designers know how to involve a player in epic space battles. Look at Mass Effect 1. When the Saren's Geth start attacking the Citadel, you're actively pursuing Saren to bring his plans to an end. When Sovereign starts to slaughter the Alliance fleet, you draw his attention into the Presidium Tower by killing Saren, twice, giving the Alliance the chance it needs to destroy the Reaper. This gives the player a sense of empowerment, rather than uselessness.

So, now we're on Earth. What happens then, with the level? Shepard kills an AA cannon, allowing most of Hammer to land safely, and then the march on the Beam to the Citadel commences. Now, this level was excellent. For one, you get to use the M-90 Cain, which was my favorite heavy weapon from 2, and you get to feel like a hero, because you save thousands of lives from a fiery aerial death. You bring down another Reaper. That was excellently done.

But after this is where the real problems arise. For the final march, you and your squad escort a few tanks across no-man's-land, to the Beam. At the end of the level, you use the Normandy's firing solution system and some land-based nuclear missiles to kill another Reaper. I'll list off the problems here.

• At level's start, you get a chance to talk via hologram to all the characters you've come to care about. You say a few lines, and then farewell. Now, this might be a realistic portrayal of wartime relationships, but that's not how Bioware has worked in the past. Mass Effect 2 was entirely about inter-character relationships. To throw all those down the tube with a couple lines is counterproductive.
• The army you escort is entirely Human. If you saved Wrex, you get to see him make a speech, but the rest of the level, every character but your two squadmates is human. The entire game up to this point seems meaningless at that point. What was the point of gathering all the races together to retake earth, if you only see Humans fighting Reapers?
• You kill one Reaper at the end of the level. The same type of Reaper that you've slain two times before in the game: on Tuchanka with the Mother of Thresher Maws, and on Rannoch with the Quarian Fleet. This is not climactic at all, in my opinion. You have gathered together the armies of a galaxy, learned the weaknesses of this specific type of Reaper, and you can only take down one on the ground.

Then, Harbinger lands. I think a similar sequence to what is currently in game is appropriate. Harbinger is the leader of the Reapers, he should rightly be able to destroy the whole ground force as it charges to the Beam. You should have to watch as the characters you love get roasted (not all of them, maybe some randomized, or some system like ME2 where the most loyal and best at defending and surviving live, but some die). Then, Harbinger's beam lands on you, and you, burned and bleeding, limp into the Beam.

Aboard the Citadel, I think the sequence plays out well. The interplay between Anderson, Shepard, and the Illusive Man is well done, and I wouldn't change much about it, if anything. But then we come to the second problem.

Deus Machinarum: God of the Machines

The Catalyst is talked about the whole game, as some mysterious entity or object without with the Crucible will not be able to defeat the Reapers. As I played through the game, I always kept thinking about what the Catalyst would be, and I came to the following conclusion.
The Catalyst is Shepard. It has to be. A Catalyst is the device, force, or material that allows a process to move forward, and I can't think of a better example than Shepard. She's the one who found Tali, giving the Council evidence it needed to disavow and pursue Saren. She's the one who absorbed the knowledge of the Beacon, giving the Alliance the knowledge it needed to prepare to fight Sovereign. She's the one who brought a team together to stop the Collectors. She's the one who, through the entirety of Mass Effect 3, helps the races negotiate, unite, and prepare to fight. Without Shepard, nothing happens. Without Shepard, it's just another cycle of extinction.
It seems entirely appropriate that Shepard be the one who has the power to stop the Reapers. It makes complete thematic sense. Imagine my surprise, therefore, when the small child from Shepard's dreams walked up to me and started talking about the inevitability of civilization's doom.
The Catalyst is, of course, a mysterious figure. His existence and origin are not explained, his motives are muddy, and his arguments are strange. I like that he has the appearance of the child from Shepard's dream (and it makes sense that he would, since he needs to be processed by Shepard's mind), but that's just a good detail in an otherwise flawed vision. Here we have a being of incredible power, one who controls the Reapers and Mass Relays, whose “body” is the Citadel. He doesn't explain how he exists, who created him, but he has decided that, because of the problem of synthetic life, organic life must be “harvested” to prevent its destruction at the hands of its own creations.
So let's look at the holes in that logic:

• In order to save organic life, the Catalyst is killing organics every fifty millenia. Paradox incarnate.
  
• If he is so keen to prevent Synthetic life from destroying Organic, why does he not just prevent Synthetic life from accessing the Mass Relays? He clearly has the ability to manage many fronts, since he can control all the Reapers. If his concern is the rise of Synthetics over Organics via the Singularity, all he needs to do is hamstring Synthetics' abilities. Reapers can already hack. It would be easy. No death needed.
  
• We see two clear examples in the same game which disprove the Catalyst's ideas: EDI, an AI who awoke and began killing, learned to rewrite her own software and care for human life, and in effect become a living, loving person; the Geth, who only ever used violence in their own defense, were willing to re-ally with their Creators as soon as the Creators gave up on trying to eradicate the Geth.
  

Now, the Catalyst admits “my solution won't work any more.” But he says it, not because of EDI and the Geth, not because of the destruction he's caused, but because Shepard made it to the point of speaking with him. The only way I can really describe this entity succinctly is as a failed deity. Such things can be used well in games, of course, but this is Mass Effect. This isn't a game about angels and demons, it is about heroism, victory, and sacrifice, about hope and free will. He is fundamentally unfit to be a character in this universe.

#RRGGBB: The Final Choice

The Catalyst gives you three choices

• Destroy all Synthetic life in the Galaxy, which means the Reapers, the Geth, the Citadel, the Catalyst, and the Synthetic parts of Shepard herself. Shepard is most likely to die, but with enough War Resources collected, she will survive.
  
• Control the Reapers, pulling them away from Galactic society, but destroying the Citadel and the Mass Relays. Shepard herself will be consumed, but her consciousness will continue to control the Reapers.
  
• Synthesize your essence into the entirety of the galaxy, joining Synthetic Life and Organic Life into one and the same thing. This also destroys the Citadel and the Mass Relays, and Shepard herself.
  

Everyone who's played the game through knows this, of course (unless they didn't get all the possible endings because they weren't completionists). The choices are ultimately these: certain victory at a heavy cost, withdrawal of the threat at the cost of yourself, and fundamental change to the universe. So what is wrong with this? At first glance, nothing. The choices are clearly disparate, and each has a different set of consequences.
The first choice will cripple current society as synthetic enhancements cease to function and robots designed to help Organics function fail. However, it saves society, and allows people to rebuild; unfortunately, they're going to rebuild Synthetics, since they don't know about Shepard's choice.
The second choice will withdraw the threat at almost no cost, but then Shepard, who is so good, will be handed the ultimate power over life and death. Power corrupts, and absolute power corrupts absolutely. There's no guarantee that Shepard will stay benevolent, becoming in essence a deity. Her mind may be fundamentally altered.
The third choice puts the entire galaxy in a situation unknown, the outcome of which is impossible to guess at. Any attempt is as useless as guessing what will be invented in 30 years.
These are each interesting choices, which are intriguing to think about with respect to their consequences. But they fall flat, not because of their nature, but because of their execution and their themes.

Execution

This is the second biggest problem in the entire game. A game which is entirely about the player's choices and their consequences ends with what boils down to an RGB selector for the final cutscene. Almost no details are different between the ending cinematics, except for the textures on certain meshes, and the color of the Citadel Explosion Beam. The Reapers leave/die, the Citadel and Mass Relays explode, and Shepard dies (most of the time, except for completionists).
And of course, that might not have been noticed, except for the fact that after the credits, the game, through Buzz Aldrin, explicitly tells you “Hey, you should play through that again and see what happens if you make different choices!” And then the player is met by the same damn thing.
It's no wonder that Reddit and other community sites are filled with posts about how empty the ending left them. Several people have posted to /r/masseffect that they don't want to play the franchise any more, because they know how meaningless their choices ended up.
But it was still salvagable given those choices. Even a choiceless ending could be made to feel good, as long as the conclusion really concludes the story. Instead, we get absolutely no fourth or fifth act in the traditional 5-act structure. The game opens with the call to action, then consists of rising action, hits the climax, and then ends. We get no news of what happens to the galaxy, no feedback as to the consequences of our choice. That breaks the entire feel and narrative of the game. And that leads me to the biggest problem.

“That is why you fail:” Themes and Plot Holes

To make this point most effectively, I need to go deeper. I need to go to the deepest principles of narrative.
An ending to a story is meant to be satisfying, wrapping up the themes of the story into one cohesive, complete moment. All of the deep questions are asked of the audience/reader/player, and the narrative either supplies an answer to those questions, or leaves the a/r/p to ponder them, seeing the consequences of the characters' actions. Clearly Mass Effect wants to leave players pondering, but what are the questions it has asked throughout the series?

Hiding in Plain Sight: The First Question

The games have never been all too subtle with their themes. In fact, they make them into plot points, but that has made people look at them only as plot points and not as themes. The most important question, which was asked as the final moral choice of Mass Effect 1, is this:

• What is the role of humanity in galactic society? Are we to conquer and rule, cooperate and assimilate, or isolate ourselves?
  

At the end of Mass Effect 1, you either tell the Fifth Fleet to save the Citadel's fleets, including the Destiny Ascension, on which the Council rides, or abandon them to their deaths, saving the full might of the Fleet for the battle against Sovereign. At first glance, this looks like a Machiavellian question: do you sacrifice some to save many? Or do you save the few in the moment, knowing the deaths you're ensuring in the future?
However, anyone who finishes the game realizes that it is Shepard's actions that ensure Sovereign's death, not the decision to save the Fifth Fleet for Sovereign. So, the choice is laid bare, especially seeing the final cutscene. Is Humanity meant to rule the galaxy, or join the Council as an equal voice?
This theme is set at the front and center in Mass Effect 2, when the Collectors are targeting Humans and Cerberus resurrects Shepard to fight back. The Human councilor is treated with disrespect by the other Council members, and Shepard is snubbed, sent off to make trouble in the Terminus systems. Cerberus makes constant attempts to set Humanity a few steps ahead of the other races. Most conversations with the Illusive Man revolve around cooperation vs. dominance. At the end of the game, you're asked whether it's worth using horrible technology, if Humanity will be able to use the technology to dominate the other races.
Then, in Mass Effect 3, everything is about Earth. You go around, looking for allies to save Earth. The Reapers target Earth. Earth, Earth, Earth, Earth, Earth. They throw this in your face the whole game. They want this on your mind, at all times. It's the most important theme in the games.

Isaac Asimov, eat your heart out: The Three Laws of Robotics

If you thought the Human Dominance/Cooperation was obvious, just look at this: Synthetics can reach a point where they become more advanced than their creators, and can rebel. If anyone missed this, they thought that this was CoD and the plot doesn't matter, because Bioware says it to your face sever thousand times with the Geth and Quarians. The whole idea of EDI is based around this, the main enemy of ME1 is based around this, and then you have Tali and Legion in Mass Effect 2. Finally, Mass Effect 3 brings you to Rannoch where you, with sufficient Paragon or Renegade, can foster a peace between Synthetic and Organic. So, the question here is:

• Can post-singularity technology coexist with organic life?
  I don't think I need to say much more on this.
  

Red vs. Blue: Moral Choice

This is, of course, one of the two centerpieces of the Mass Effect series: the ability to choose how you talk to people, and so how people will treat you in return. The theme is so centric and important that one of the mechanics is entirely based on it. So, just to phrase it as a question, because I think it's really obvious:

• Should you be nice to people, or should you be a badass?
  

So what now?

All right, we have our three central themes. Now, we need to apply them to the ending.

Let's Start with the Obvious

So, the Catalyst speaks entirely about the second question. How can synthetics be prevented from destroying organic society? Clunky dialog aside, this is addressed well. I wish Shepard got to have a debate with the Catalyst about this, but that's more dealing with theme 3. So, mark this one handled.

What about Humanity?

All right, so the Citadel's at Earth. And Shepard's a human. But what else happens in the final level that challenges people to think about where Humanity should stand in the Galaxy? Everything to do with the choice is just synthetics or organics. This isn't even mentioned after the Illusive Man dies, and even then, it was about controlling or killing the Reapers, not Human dominance. This one is marked as not handled.

Moral Choice

On its surface, the ending offers this, to those who have enough War Assets. Of course, if someone rushed through the game, no dice. But even worse than that, the choices don't matter, because of the execution. So nominally, this question is handled, but not at all well.



And there we have it. The ending of Mass Effect 3 fails, because it doesn't offer meaningful choices in a game about choice, it doesn't address a major theme of the series, and it only shows a cutscene that answers few questions, and cuts to credits.

But what could be better?

All right, time for my indie designer ass to get in gear. It's all well and good to call something crap (hell, I do it all the time, I'm a Redditor). But it's another thing entirely to suggest something better. So here I go.
First up, the goals of the ending(s).

• Force the player to consider the Five Questions (Three Questions).
  
• Bring all the various conflicts which have not yet been resolved to a head at the climax, resolving them all in one moment of pure epic.
  
• Let Shepard be the Catalyst. Yes, I'm very set on this, because the games are all about Shepard's heroism.
  

Along with this, we should consider the strengths of the Mass Effect brand

• A rich galaxy filled with immense diversity.
  
• Excellent cinematic arts
  
• Well-written speeches (on the whole)
  

Let's begin with my third-favorite moment in the game. (For those curious, #2 is the last 5 seconds of ME2, and #1 is Mordin's singing at the Shroud)

Carrier Has Arrived: The United Galactic Fleet

Cerberus has fallen. The fleets are prepared. The Crucible is complete. It's time. The might of a galaxy descends upon the Sol Relay to bring the fight to the Reapers. The UGF warps through the relay, assembling a firing line as it moves toward Earth. The Reapers respond, and the fight of all ages commences.
Meanwhile, Commander Diana Shepard, Hero of the Citadel, Savior of the Council three times over, Guardian of Humanity, the First Human Spectre... Is in a shuttle flying to Earth.



What.
The.
Hell.
I understand that Shepard isn't a fighter pilot. She's a soldier. But this is the final battle of the war. If this ends badly for the Organics, the cycle continues, if it goes well, galactic society advances to unknown heights. Shepard needs to take part in some way. So how can a soldier take part in a space battle? There are two options, as I see it

1. Downscale an enemy and let Shepard fight that enemy on a space station ala Saren/Sovereign
   
2. Let Shepard use some weapon to take part in the battle in some meaningful way, wihtout being the focal point of the fight.
   

We see that Bioware prefers to use option 1, from the fight with Saren and the flight through the Omega 4 Relay. However, in this case, I think option 2 is more appropriate. So here's how I set it up.

We're gonna need a bigger gun: The flight to Earth

Cortez is a nice character in this game. He's never incredibly important, but he plays a good supporting role, has nice character to him, and is written very well as a gay character. I think he deserves his moment to really shine. Let's jury-rig all the shuttles that Hammer takes down to earth with manned turrets. Then, as the space battle begins, the fighters launched by the UGF escort the shuttles through the battlespace, fighting off the Oculi launched by the Reapers. Shepard mans one of the turrets.
As the flight progresses, you get to watch incredible explosions on both sides. I'm thinking Asari Destroyers and Reapers exploding in front of your eyes. Shuttles shot down, various races suffocating in space. Let the Level Designers and Cinematic Artists go to town. This can be an great moment that drives home how hopeless the fight is, or how well the UGF has prepared.
Then, when the shuttles near the surface, you show the Anti-Air Reapers destroying swathes of shuttles. This transitions well into the first level set on Earth since the opening of the game. I think it fits far better than a simple shuttle ride and a cinematic.



I really liked the level where you take down the AA Reaper. It's well designed, well laid out, the final waves are very challenging, and you get to use the Cain again. That was the most fun weapon, in my opinion, from Mass Effect 2, and I was glad to see it return, and so appropriately (it was the best way to kill the Human-Reaper in ME2, why not use it to kill more).

Where have all the good men gone: The fight through No-Man's-land

The planning stages and main Earth-based level left me profoundly disappointed. I've already outlined the main issues with it, so quick refresher: You've already done everything you do in this level, before. You've killed Reapers. You've pushed across Cannibal-infested lands.
But the biggest problem is the lack of allies. It's you, Anderson, and a bunch of Human forces. What happened to the Geth Primes for whom Legion sacrificed himself? Where are the armies of young Krogans? Where's that incredible Turian army I keep hearing about? Let the player see how well they've accomplished their goals. Bring along the whole army. London is a very large city. Let's see the whole thing in ruins, with millions of husks, thousands of Cannibals, all over the place. I don't want a quick run down Downing Street, I want to see England explode like it's 1942. Everything about this level should be about united forces, desperate odds, and huge battles.
So, laid out simply: In the beginning of the level, all the squadmates Shepard has ever had, who have survived to this point, meet at the war council. Bring in Anderson and the Brit from the reveal trailer, and you've got an assembly of the biggest heroes in the galaxy.
They discuss what they have to do, and realize that they can't do anything but a full-on assault. The armies assemble, Shepard picks his squad, and the rest of the companions move out to head the various platoons in the battle.
Shepard gives an impassioned speech, which is broadcast over the intercoms of the whole army. I'm thinking of the cutscene before All In from Starcraft 2: Wings of Liberty. Start the rain, lightning, message of hope or badassery (paragon/renegade choice). War cries, and a charge.
Then, the biggest level yet seen in Mass Effect. This is the culmination of three games. It needs to make the word Epic insufficient. It needs to blow everyone's mind. There should be views available of a hundred charging Krogan, firing shotguns and screaming like madmen. There should be Kasumi, darting around the battlefield blowing Banshees' faces off. There should be Ashley, gunning down husks left and right. There should be firing lines of tanks obliterating Ravager forces. All the while, Shepard leads the force through the decimated city, inspiring troops and defending necessary tanks.
Then, the army nears the beacon, and down come the Reapers. At least 5 Destroyers, at least 2 full-size True Reapers. The battle is intense. Thousands are melted. All missiles are launched. The fight seems nearly lost, when Shepard pulls out all stops, EDI uses her technological prowess, and the Reapers in the battle fall to the ground. Shepard and her squadmates climb over the sparking red and black corpses, walking down to the Beam.
Then comes Harbinger. The first and greatest of the Reapers pulls away from the battle in space to see to the situation himself. He melts entire battalions with a single beam of light. Your forces scatter. You see your allies desperately trying to hide, watching squadmates melt in the ungodly rays. You are almost to the Beam, mere steps away. Then, Slo-mo. You see Harbinger's eyes turn on you. You watch as a tentacle rises, and points right at your feet.
Red.
Then, watch as Harbinger flies away, burning more troops along the way.
Cut to the long walk; Shepard, badly wounded and bleeding, limps to the Beam, and the end sequence is triggered.
Isn't that so much more awesome? I can see it in my mind, and, well, I drop all pretense of modesty, because that would be absolutely incredible and f*** you for disagreeing with me.
We know that Bioware is capable of all this. We've seen scripted sequences mid-battle. We've seen main characters die based on pre-defined criteria. We've seen epic battles. I just want all at once.

Screw you, kid: The final choice

So, you and Anderson are the only two to reach the beam. All the rest of the UGF's ground forces are either ashes or retreating. Cue The Illusive Man, with his new Indoctrination powers. I loved this sequence. The only complaint I have is that I only get to hear the Illusive Man's last words as he looks at Earth if I shoot him myself, instead of convincing him to commit suicide.
But now, we get to the worst part of the game. That freaking KID! Who the hell does he think he is? I'm the bloody Catalyst. So how do I change this?
First off, I do approve of the choice to have the kid from the beginning and from Shepard's nightmares come up to us as a hologram and talk to us. It's an appropriate choice. But instead of the RGB nonsense he throws at us, here's what he says.
“You're not the first. The Crucible has been completed before. I'm here to tell you why we are here.”
“We?”
“I am the soul of the Citadel. The last remnant of a long-dead race. Countless cycles have gone by since my Creators walked these halls. They, like you, evolved to the point where their technology surpassed them. The created surpassed the Creators. And so, the Creators found a solution. The salvation of every species ever to evolve to the point of Singularity. Salvation, through destruction.”
“They created the Reapers.”
“No. They became the Reapers.”
Et cetera, et cetera, et cetera. I'm no good at Dialogue, but you get the idea. At some point, talk about how Shepard is the Catalyst, the one piece missing from nearly every cycle. So rare is a person like Shepard, who is able to unite a galaxy, prevent the Reapers' return via the Citadel, destroy the last cycle's Indoctrinated, and live to fight the Reapers as they arrive. Eventually, you are left with the following choices:

• Destroy the Citadel. Doing so will destroy the “Catalyst” (who I'll now call the Child), and leave the Reapers leaderless and directionless, killing most of them and weakening the remainder. However, Earth will also be destroyed in the explosion, along with most of the UGF and all the forces on the ground. Shepard will, of course, die in the explosion.
  
• Assume direct control of the Citadel, and so the Child. This won't grant the godlike powers like the current ending, but will instead let Shepard fight with the Reapers' minds, weakening their bodies and leaving them vulnerable. Losses will be severe, but Earth will remain, and the Galaxy will be able to rebuild. Shepard will be killed.
  
• Destroy the Child's core, leaving the Citadel intact. The Reapers will not be weakened, but will lose intercommunication. The UGF will be able to isolate and kill them one-by-one, bringing the cycle to an end.
  
• Flip off the Child, nurse your wounds, call Joker, and get a shuttle back onto the Normandy. You're doing this the old-fashioned way, dammit. You won't take any of that kid's crap. If you've collected a huge amount of War Assets, you watch as the UGF slowly whittles down the Reaper force, until only Harbinger remains. In a final, massive fight, Harbinger destroys most of the UGF, but explodes, his parts falling to Earth.
  

These choices need refinement, but they satisfy all three of the themes. Do you sacrifice Earth and the militaries, in exchange for saving the galaxy? Or do you sacrifice yourself to give Earth and the UGF a fighting chance? Do you pull the ultimate badass, and just say “You know what, we don't need the Crucible. We have ammo?”
Finally, after all of these different choices play out, you get to see the results. If one of the first three choices is chosen, either Shepard or Hackett gives a speech as we see scenes from Tuchanka, Palaven, Rannoch, and Earth, showing us the consequences of all our actions. If the fourth is chosen, we either see that, or the Reapers overtaking the galaxy. Watch as Garrus is turned into a Marauder, as Hackett becomes a Husk. Show us the true depths of our failure.
That will give people their Dénoument. They'll get to feel the Catharsis. That, in short, is a bloody ending.

---

Addendum: Arkis from DeviantArt wrote an amazing extension to the current ending which beautifully incorporates the current ending into a new, much more full, better ending. http://arkis.deviantart.com/art/Mass-Effect-3-Alternate-Endings-SPOILERS-289902125