MASS EFFECT 3 - THE PIGLET CUT
The first problem with the game is this. How are we expected to believe that an unprepared, in denial Earth can hold off the main thrust of the Reaper fleet while Shepard charges around the galaxy solving everyone else's problems? I mean, I know humanity is kind of a sleeping giant to the point and the other races think we're a bit weird still stockpiling thousands of nuclear weapons from the Cold War, but all the same, it's just not believable given what we already know about the Reapers. So this has to change. Also, the Crucible? Fucking deus ex machina magical bullshit device that they knew about all along and just happens to be fully translated on time. That's got to go as well, or at least be reduced from "magical bullshit device" to "thing that makes sense within the setting and has realistic, within the setting, effect."
Solve these two problems, and we won't end up with no option but pick the colour of the big bang as the explosion as an ending.
As before, we open with Shepard grounded on earth after he destroyed the Alpha Relay and killed 300,000 batarians in the process. People on Earth believe that the Reapers are coming now, well, sort of. Not enough to get Shepard mobile again, but they are at least listening. Unfortunately the listening involves days of arse-numbing debate on Earth as to what we do about this and Shepard getting increasingly frustrated with having to walk yet another bunch of bureaucrats through the evidence they've collected of this from the first two games.
One day, Anderson comes to Shepard's quarters / cell (depending how you look at it) on Earth and tells them that they believe them, and that the batarian capital of Khar'shan just went completely dark. And the evidence is that the Reapers are real, and that the main prong of the Reaper fleet is heading for Earth. Anderson takes it upon himself to basically spring Shepard from Earth and get them into the Normandy again with a skeleton crew, while he stalls the politicians long enough for Shepard to get away and to go and collect allies and assistance to fight them. Tutorial level where Shepard has to bust themselves out ensues.
On board, Shepard then has a number of leads which could be several of the actually good main and side quests from the game. We'll leave them alone. However the design can be different. Rather than an infinite timespan to do everything, the whole game should be on a timer. The galaxy map should start having systems and clusters blacked out after each quest and marked either "dangerous" which means potential to be interdicted by Reapers, or "dead" which means, well, dead. The progress of the Reaper fleets should be linked to the number of quests Shepard has done and Shepard gets tip offs about quests throughout the game. All of them should be on a timer (i.e. like how Grissom Academy was). You don't get there in time, they fail. If the Reaper fleet reaches Earth, Shepard is forced to drop what they're doing and go back there for the endgame. And if Shepard doesn't have key items or information, Earth WILL be destroyed before Shepard can get there and Shepard will be treated to a hijack of their QE comm from Harbinger as he assumes direct control of the relay network forever and explains that Shepard has failed totally. Long shot of Shepard collapsed in the conference room in a state of total catatonia. Roll credits.
The number of places and people Shepard manages to save or sign up for the big battle will both lower the difficulty of the endgame AND affect the quality of the ending as a whole. It should be emphasised that several will be mutually exclusive and Shepard's character development in this game should be that they can't save everyone. They can go back to the Citadel every now and then for shopping trips or political machinations but this chews up time which they don't have. In fact, it should be designed that you can't get more than 75 percent of the quests done even with optimised efficiency.
If Shepard manages to find the bits of the Crucible then this will give them a shot at the endgame. In the endgame it plays out much like it does in the game as we know it but without the whole "for some reason the Citadel has been towed to Earth" nonsense. Harbinger has showed up in person, and Shepard has to get into him and deploy the Crucible which turns out to be a piece of sentient malware that can override and force the suicide of a Reaper flagship. However it has to be applied to the Reaper directly at its core. Shepard does this, blasting through all the huskified bad guys and Marauder Shields (he's staying, definitely, maybe make him into a real boss fight) and clambers into Harbinger's core. Malware applied. Shepard collapses utterly exhausted and Harbinger destroys itself and the malware also causes significant damage to the rest of the Reaper fleet. They run and flee.
Shepard is, of course, dead. They never found the body.
The ending then is a lengthy montage showing how the rest of the galaxy fought back hard and that Shepard's apotheosis on Earth was basically a Stalingrad moment. All of a sudden sentient life is up and fighting and destroying the Reapers and though it takes them fifty to a hundred years (subject to Shepard's decisions across the trilogy and the outcome of the various subplots), eventually the Reapers are defeated for good. A modular ending shows how the choices the player made shape the situation of the rest of the galaxy. A Paragon run would be that they are all having difficulty rebuilding but generally working together and life is hard but there is a real feeling that we can build a better galaxy. A Renegade run shows humanity acting in an expansionist and irredentist way and towing the other species behind them regardless. There can be other endings for the other species out there.
In a final scene, an elderly Anderson (who survived) chisels Shepard's name into the stump of one of Harbinger's claws which was left behind embedded on Earth. Zoom out to reveal that it's surrounded by the names of millions of other characters who died in the war. Maybe old versions of other characters, like an aged Kaidan / Ashley who is the President of Earth, their various henchmen (Garrus would probably be the Turian emperor, Tali and/or Legion or both as representatives of Rannoch, Wrex would show up with Eve riding tandem on a dinosaur and a horde of cute krogan kids following, Liara in her archaeology gear possibly with her and Shepard's daughter if she was the main love interest, Kasumi and Jacob holding hands, blah, blah, insert fanservice here). And finally, a very old man in a wheelchair giving the ending narration to his granddaughter on some moonlit hillock about a tale of the Shepard like in the game we know, but who turns out to be Joker. But adding to it, he says that perhaps we need a Shepard more than ever know, what with the stars going out. And as EDI wheels him off stage left, the sun rises, only to be a baleful, aged red carbon star like Haestrom's sun was in the second game, and that maybe there is something even worse than Mecha Cthulhu out there (Alexa, what is an obvious sequel hook).
Credits music? Probably "Forevermore" by Iron Savior.
