So, I read this Gamasutra article by Jason VandenBerghe, and I basically want to argue the exact opposite.
Endings are extremely powerful. Arguably the most powerful part of any story, with the only close competitors being the opening and the main twist. A good ending can leave your audience in stunned silence for minutes, or screaming and bouncing off the walls. It leaves a deep and indelible mark in your brain.
Not all games need endings, but if your game has an ending, it should probably have a good one.
That said, Jason's article is not wrong. Most players don't finish games. And most games have shit endings. And... I know this will be a shocker... most games are just badly written.
For example, Bioshock is brought up. Bioshock and its successors have fantastic art direction, great voice acting, and a powerful sense of place. They are good places to be. But, in terms of writing, they're barely high-school level. "Would you kindly" is a shadow of a twist, and the ending is a few still images and a narration.
I won't say that the writers are bad. The problem is not how skilled they are, but in how the games are written. Budget constraints, convoluted development schedules, and boardroom interference can turn an excellent script into porridge... or a festering garbageheap into porridge. Either way, you get porridge.
Jason was right to enjoy the play of Bioshock and not give a shit about the ending, because that's how the game was built. But it's not how games must be built. We can use endings.
This is a two-step process.
1) Have a good ending.
2) Increase the percentage of players that reach the ending without making the game "too short".
Having a good ending is obviously a bit of a challenge. There are a lot of classes and tutorials about how to write one, but in our case we need to focus on techniques which allow the ending to retain its power even through the chaos of an ordinary development cycle.
The chaos of how a player plays your game is a similar concern. Some players pay more or less attention to different aspects of the story, or have different maturity levels. They may be in a good mood or a bad one. Maybe their kid starts crying halfway through your lead-up. All of this chaos!
How can you build an ending on sand?
Well, I can't recommend a twist ending.
Twists are easy to screw up. A twist is something the audience doesn't see coming, but when it happens they feel like it was both inevitable and mind-blowing. That requires a lot of lead-up to set the stage, and that lead-up will be ruined. Players won't notice, or they'll be smarter than you expect and notice it way ahead of time. The dev cycle of the game will cut a level out and exclude a critical clue. Someone will post a spoiler on Reddit and it'll get a billion reshares before the game even goes live...
Now, you can put twists into a game. But I would put them near the middle of the game and make them simple progression twists instead of a perspective twist. By these standards, killing Crono or letting Kefka blow up the world were good twists. You can't misunderstand them, you can't overly predict them, and it doesn't matter if the level leading up to them is cut or badly damaged during the dev cycle because there's no critical info in it.
For an ending, I recommend thematic echoes, a straightforward epic setpiece involving sacrifice, and a post-ending wind-down.
Thematic echoes are good because they don't require any one plot point to exist and don't require the player to be consciously paying attention. The easiest thematic echo is to look at what the player accomplished and then leverage that for catharsis or drama.
For example, if the player spent the game gathering squadmates, now the player must spend those lives to protect the world... or let the world rot to protect the squadmates. If the player has protected the townsfolk, now those people show up to protect the player. If the player killed a bunch of slimy aliens, now the player has to protect a bunch of slimy aliens - or be one, who knows. The point is, the player has been doing stuff, and they'll have an attachment to that stuff even if they don't consciously remember it in detail.
Epic setpieces are an obvious element of a good ending, but you'll need to add an element of sacrifice to really show that this is not just another boss. This is the end. You want that tingle to crawl down the player's spine when they suddenly realize that the story is going to end here. Things fall apart. People die. The main character loses an arm. These losses need to be of the sort where the story cannot continue as it was. This is the last stand.
The wind-down is also critical. Too many people just put up the ending and then ditch to credits or a pop song or something. It takes a little while for a good ending to finish crushing people's brains, so leave that ending scene uncut for at least ten more seconds than you might think you should. Nobody's in a hurry to see your end credits or hear you pitch your next YouTube video or whatever. Let them process what you've just given them.
Good wind-downs may also serve as follow-ups. For example, in Suikoden and Fire Emblem, the wind-down tells you how each character spends their life. It's very well-done.
These are just my suggestions, but I hope you can see how an ending built around these principles can survive the chaos of development and a wide variety of erratic players.
You want players to see your ending.
To me, the ending is like a tattoo needle, and the rest of the game is like ink. Yes, players will end up randomly covered in ink as they play, and it'll leave a mark. But the needle is what gets it under their skin forever.
The problem is clearly explained in the article Jason wrote: games are long. People have different amounts of time, investment, and interest.
Fortunately, there are a lot of methods we can use to deal with this.
One way is to move content to after the ending. Post-ending content is a fun tradition, and there are three basic varieties.
1) The game continues. Somehow you continue to run around the world doing stuff even after the end.
2) Last-save options. You can always load up that save just before you commit, and go play in the Gold Saucer for a decade.
3) New game plus. Things unlock if you play again.
Just be sure not to make people think new game plus is required to get the "true ending". Crono Trigger did this right: you get the true ending when you play it through. The endings you find in new game plus mode are just fun alternatives. The ending they get is a tattoo. Don't let them think you gave them a shitty tattoo.
Another method is to use "multiple endings". Rather, you should think of major arc events as things that will be "endings" for players that stop early, and the next hour or so of play would be the wind-down from those endings.
A good example of this is Final Fantasy 6. Kefka blows up the world in the midgame, and you spend the next few hours seeing how your friends are surviving in this new world of ruin. From a story perspective, this is an excellent midgame twist. From our perspective as game designers, this is simply "ending A". People get to see the epic setpiece where the world is destroyed and everything comes undone, then get to wind down. It's a "downer", but that's not bad. It's just a skull tattoo instead of a heart tattoo.
It's not the "true ending", but you didn't do a bait and switch so it should be okay. It's just a memorable moment that can serve as an ending for rushed players.
Another method is to use "stretch content".
Most of the time we think of optional content as "completionist fodder". Like, do you collect every Pokemon? Take every picture? Level every item? Find the secret smooglesboogs?
But it's so much more flexible than that. Optional content is an incredibly powerful way to let the player tell you how much time they have, how tense they are, and what they care about.
For example, loyalty missions in RPGs. A lot of players will only do one or two loyalty missions for their favorite party members. Others will do all of them.
Why not just... extend that?
Major characters in these kinds of games usually represent a core story aspect or theme. So the story elements you planned to put in the main game to stretch it out... stick them in the appropriate character's repertoire. Not one loyalty mission per character, but maybe one loyalty mission per character per world, or perhaps a loyalty mission for every given pairing of characters.
Since your ending is built with our resilient approach, how much of this stretch content the player uses is largely unimportant. As long as that ending is still the "true" ending - too many games require you to do the side quests to get the "true" ending, and that's the opposite of what we want.
Content like Disgaea's item dungeons or Final Fantasy's optional bosses can also extend play time. It's not thematically integrated very well, though: I prefer the character-driven side missions, since the characters are thematically integrated.
Either way, the point here is to be vultures rather than tour guides. We push the player to feel things and control the tension, but we allow the player to tell us how they feel and how tense they actually became. The chaos of a game is impossible to predict, so we need to allow the player to control their own experience with a bit more adaptability.
Anyway, those are my thoughts:
Endings are powerful. They take the raw experience of the rest of the game, and push it under the player's skin. A good ending will use that ink to draw something cool, and the player will remember the game forever.