Heartwarming: X-Men vs. Street Fighter aka: X-men Vs Street Fighter
In Gambit's ending, we see Rogue thinking about not being a human. Then he approaches her. And they hug each other. Awwwwww...
—> Rogue: Darlin', what does it feel like to be normal.
Chun Li: Don't worry. I throw fireballs, that's not normal.
Ken's ending shows that his entire playthrough has been a game with his son (who looks exactly like him) and Eliza calling them both to dinner. It's very sweet to see that the brash warrior has settled down, found peace and happiness.
Storm's ending, too. She and the X-Men are releasing several fighters and mutants that were caught by Apocalypse, and she tends to a wounded Forge who has just been released. in the background, Sakura is happily talking to Gambit — and Dan hibiki is, well, himself.