Sliding Scale of Endings

Originally, the word "comedy" meant that the story ended on a positive note, and the word "Tragedy" meant a Downer Ending (or, at the very least, a Bittersweet Ending). The meanings of these words have evolved over time, but the concept remains: Some stories end happily, and others...not so much. This is a scale of how happily a given story is bound to end.

Good Ending

 * Golden Ending - Top of the list, variant of Multiple Endings. Usually invoking Earn Your Happy Ending. Everybody Lives is generally a prerequisite.
 * Happily Ever After - The good guys win, the bad guys get their comeuppance or redemption (depending on the villain), and everyone is happy.
 * Earn Your Happy Ending - The good guys will have to slog through a great deal of mud and tragedy first, but, ultimately, everything ends well. At least, for the ones that survive.
 * Everybody Lives - Exactly What It Says on the Tin.

Neutral Ending

 * Bittersweet Ending - The good guys win, but, due to some terrible tragedy, they're not going to be happy about it. Or they die, but everyone else is happy.
 * Pyrrhic Victory: Heroes win, but their victory means nothing.
 * Pyrrhic Villainy: The Bad Guy Wins, but his victory means nothing, and the conflict continues.
 * Multiple Endings - A character's actions in the game decide how the ending turns out.
 * No Ending, Bolivian Army Ending - The ending is ambiguous. Did the heroes win, or did they all die horribly? The author or creator ain't talking, so it's up to the viewer to decide.
 * Gainax Ending - The ending is confusing and full of Mind Screw; differing interpretations can lead it to being placed in any of these three categories.

Bad Ending

 * Downer Ending - The good guys lose. They might at least get to take the villain down with them, though.
 * The Bad Guy Wins - Or not.
 * Have a Nice Death - You've lost the game and are dead but at least you get a cheery message about it.
 * Shoot the Shaggy Dog - The bad guys win. Or nobody wins and the whole ordeal is a waste of time and human lives.
 * It's a Wonderful Failure - A game player has screwed up big time and has to watch the repercussions.
 * Cruel Twist Ending - An story that screws the heroes at the very end.
 * Diabolus Ex Machina - Similar to the above, but it comes out of nowhere.
 * Esoteric Happy Ending - Happily Ever After in the mind of the writer/director, Downer Ending or Shoot the Shaggy Dog for the audience.
 * Kill'Em All - Exactly what it sounds like.
 * Rocks Fall, Everyone Dies: Similar, but for a Show Within a Show under control of a character in the main show.