PixlBit

Look at this Alan Wake lookin' mother fucker right here. 

Stage Select (Warning: I really really love Mass Effect)

Set it 1000 years after Mass Effect 3. The Genophage was cured under Wrex and Eve and the Quarians made peace with the Geth, but every other choice will be up in the air and decided during conversations. For instance, if a character explains Shepard spared Kaiden, you can confirm it or correct them to say Shepard saved Ashley. I left out the Krogan and Quarian choices to ensure the two races are still in the game. The Galaxy has two councils, the more powerful one called The Alliance Council and led by:

Humans, who were spared in large numbers by Reapers to create a new one that never reached the phase where people were killed. Because of this, they weren't as hurt as some other races by the war. Their initiative and leadership were crucial the Galaxy to recover.

Quarians- Their exile ended up being perfect experience to aid other species in recovering. They still wear their suits out of tradition, but without the glass masks (unless in space) as their immune systems have recovered

Geth- If you picked destroy, the Quarians quickly rebuilt them and either way they now live as AI in ships and space suits. They are preparing to leave the Galaxy, however to join as one collective conscious. 

Krogan- Wrex led their military to wipe out any chaos after the war while Eve eliminated their archaic customs. Krogan are still known for being soldiers, but are more similar to Turians in the trilogy as they also thrive politically, economically and especially scientifically.

Salarian colonists- Splintered off from the Dalatrass, but otherwise largely the same. They want to unify, but not under the current Dalatrass' terms, favoring an uncentralized leadership.

Turians- The weakest of the main races, as they were hit the hardest by the Reaper war to cripple their strong military and still haven’t fully recovered even a thousand years later. The Krogan replacing their role has left them lost as a society. They're still a powerful race, just not the super power they once were.

The Alliance Council is far from perfect, but is trying to keep the Galaxy united, with every race having a say unless they choose to not associate. The ones who don’t form the Terminus Council: 

Asari- Created a lot of mistrust from hiding Prothean tech, with some blaming the Reaper War's severity on them. The accusation was blown out of proportion but the Asari created their own council led by Aria T'loak when the old one fell apart. Modern Asari are very influenced by her leadership, creating a cutthroat culture, with Aria's first replacement still in power and so similar there's rumors shes really Aria's daughter. 

Yahg- Aria helped uplift this race to be their muscle to counter Krogans. The Yahg are more civilized than in ME2/3 but still highly aggressive and a common enemy in the game.

Hanar- The Asari lured them with Prothean artifacts and knowledge. Hanar are good intentioned, but zealous with their Prothean religion and will assist Asari with anything.

Drell- Have recovered thanks to Asari aid and have as much loyalty to them as Hanar. They’re still dangerous assassins but their perfect memory have made them thrive in science and politics

Salarian Dalatrass- A powerful force, but a shell of the Salarians in the trilogy. Wants to use the Terminus Council to conquer colonist worlds, but is being used by the Asari

The plot of the game will work like Dragon Age Origins, letting you pick between Human, Quarian, Asari, and Drell. Each origin ends with an aged Liara asking you to join her on an expedition to stop a group of terrorists. From there, you will discover they found an ancient race’s incomplete Crucible and work for the Terminus Council, eventually revealing their intentions: If Shepard destroyed, they want to use it to take control of all Geth before they leave the Galaxy to seize control of space suits and ships to conquer the Alliance Council. If Control they plan to control the Shepard VI and bring back the Reapers. If Synthesis, they plan to hijack the Geth to locate the Reapers and conquer them. 
The player can then take control for themselves or destroy the method to control the Geth, siding with either or neither council, with the player able to both destroy both councils or force an alliance between the two. 

As far as gameplay goes, if I didn’t mention it, I agree with everything Julian says.

Cage Match:

Eternal Darkness tries to make Luigi go insane, but fails due to Luigi's already existing insanity from living in Mario's shadow. Luigi's Mansion wins.

STAGE SELECT:

Make it a space sex focused spin-off and completely reformat the gameplay to be like something from DONTNOD Entertainment, because I have no connection to this series and I'm honestly just interested in the branchin dialogue choices, specifically. 

Remember when you asked me to make the next Final Fantasy game? How'd that turn out for ya? Exactly. 

CAGE MATCH:

I have really fond memories of both, but I have to go with Eternal Darkness, only because I wish more people would play it. They're both unique gaming experiences, but I think most people who'd be interested in Luigi's Mansion have played it, whereas I feel the need to proselatyze a bit more for ED, as well as for Eternal Darkness. 

Anyway, have you thought of the benefits of ED? It can keep you from making some very stupid, life-altering decisions. It's pretty great.