So let's take a proactive approach, shall we? Spoil them for yourself before your friends have the pleasure of spoiling them for you. It'll be quick and painless – like taking off a band-aid.
Additional contributions by Henry Gilbert, Cheryll Del Rosario and Tyler Nagata
Bayonetta is the left eye. Cereza is Bayonetta. Balder is her father. Jeanne is good.
Abaddon is the Destroyer. War defeats him and summons the remaining three Horsemen to begin the Apocalypse.
Army of Two: The 40th Day
The nuclear bomb Jonah says is rigged to blow up Shanghai if he is killed is a bluff.
Aliens provided the Axis powers with alien weaponry during WWII. Will escapes the Void.
Mass Effect 2
The collectors are protheans that the reapers genetically modified to use as a slave race. Shepard and team storm the reaper base successfully and discover a gigantic human-reaper hybrid.
No More Heroes 2
Travis defeats Jasper.
Above: Mildly NSFW for butt reasons
Dante sacrifices himself for Beatrice so she can ascend to heaven, which in turn bumps Dante up to purgatory for his good deed. Lucifer escapes hell in the form of a snake?
Ace Attorney Investigations: Miles Edgeworth
Shih-Na is Calisto Yew, and she's not actually Cece's sister but an undercover Interpol agent, and actually even more secretly a member of the smuggling ring, which Quercus Alba runs. She also killed Byrne Faraday, Kay Faraday's father.
SOCOM: US Navy Seals Fireteam Bravo 3
The team destroys the cache of chemical weapons and kill Gozorof and they all celebrate by going on vacation together. D'awww. Lonestar is killed by a sniper though.
Sheriff George Woodman is the new raincoat killer. York is really named Zach. The red seeds really have supernatural power, and they come from trees grown out of a woman's stomach, specifically York/Zach's mother and Emily, who both die from the stomach trees.
The origami killer is Scott Shelby.
FromWikipedia: NIS America's president, Haru Akenaga, stated that the game was "not the kind of title we should release in the United States because of its quality", and that he felt "really sorry for our customers because we released that title."
White Knight Chronicles
Kara is the Black Knight. Setti is Grazel is the Sun King is the ultimate leader of the evil Magi. Ends on a cliffhanger with Grazel rallying like a zillion troops to war for the glory of the Yshrenian empire.
Command & Conquer 4:Tiberian Twilight
Colonel James mortally wounds Commander Parker, but in Parker's dying act he helps Kane (who is an alien, btw) activate the Scrin tower with his optical implant. Kane ascends and disappears along with all the followers of Nod. The Tiberium growth abates.
Final Fantasy XIII
Fang and Vanille turn into Ragnarok together and save both Cocoon and Pulse by creating a giant crystal pillar to prevent the worlds from crashing into each other. Everyone's l'Cie brands are removed. Sazh and Dajh are reunited and so are Snow and Serah. Happy!
Artyom either destroys the Dark Ones with missiles, or he hallucinates and spares the Dark Ones, believing them to be peaceful.
Red Steel 2
The hero kills Shinjiro, breaking his katana in Shinjiro's chest. Then he throws the other half of the katana off a cliff.
Sakura Wars: So Long, My Love
The Star Division defeats Nobunaga but he manages to escape as his castle is destroyed.
Shin Megami Tensei: Strange Journey
The three endings depending on your alignment are:
-Law: Heaven takes over the world, freeing humanity of suffering but taking away free will.
-Chaos: The demon world prevails and humans retain their free will but live by only the law of brutality.
-Neutral: You complete the mission to destroy the Schwarzwelt and the world goes back to normal.
Just Cause 2
All the countries are fighting over Panau because it has the world's richest oil supply. Panay is killed – no, wait – he's still alive! Rico attaches him to a nuclear missile and aims it at the oil fields, destroying all the oil to end the conflict.
Dead to Rights: Retribution
Jack kills Redwater. Shadow survives.
The people we think are humans are actually Replicants, which were bodily shells created to save the human race from a virus 1300 years ago, but gained their own sentience. Shades are what's left of the original humans who want their bodies back. Nier and Yonah are reunited, but in a subsequent playthrough Nier sacrifices himself for Kaine to save humanity.
3D Dot Game Heroes
The hero saves the kingdom. The princess says they can be "friends."
Lost Planet 2
The Over-G is destroyed, preventing another ice age. The mercenaries save the day.