WARNING: The following story contains endgame spoilers for Assassin's Creed III.

I never really got into Mass Effect, the epic science fiction trilogy that spanned this entire generation of game consoles and ate up hundreds of hours of gamers' lives over the course of the last five years.

So I wasn't sure what to think when many of the series' most devoted fans unleashed a furious backlash against its maker BioWare following this year's release of the grand finale, Mass Effect 3. A large group of players was quite let down by what they felt was a thin, anticlimactic ending that didn't live up to the half-decade of buildup.

After finishing Assassin's Creed III, I am beginning to sympathize.

Assassin's Creed and Mass Effect have a lot in common. Both games were unveiled during those heady days between the announcement and the release of the Xbox 360 and PlayStation 3, when every glimpse we got of next-generation videogames was thrilling. After a couple years of intense anticipation, both were released in 2007 to great success. Each game was planned from the beginning as the first chapter in an elaborate multi-part story, both of which came to a conclusion this year as the console generation winds down.

Even though the latest game, released on Tuesday, is called Assassin's Creed III, it's actually the fifth in the series (not even counting three spin-offs for portable machines) in six years. The games have starred different characters living at different points of history, but the common thread connecting them is Desmond Miles, a modern-day descendant of the assassins.

To make a very long story short, we find out as the games progress that the reason Desmond is using a computer simulation to access the memories of his ancestors is to attempt to fend off the end of the world, finding artifacts and temples left by an earlier civilization that can stop an impending cataclysm.

Reducing the story to a single pithy line like that seems unfair, when the Assassin's Creed series has been one of the most narratively rich games of the past five years. Ubisoft has even released a massive encyclopedia filled with the staggering number of characters, places and stories that the development team has painstakingly crafted over the years.

Assassin's Creed III takes that magnum opus and pops open a brand new magnum, introducing a new assassin living during the American Revolution and crafting a staggering virtual version of colonial New England for you to play around in. The gameplay doesn't fundamentally change, but the new setting injects a much-needed dose of magic: riding horses from Concord to Lexington and taking part in one of the pivotal events in human history is quite captivating.

Implicit in this epic tale spanning the last thousand years was the promise that it was all leading up to something huge, some big explainer that put a final cap on the centuries of back-and-forth between the Templars and the Assassins.

So what happens? Turn back now if you don't want to know: Desmond opens up the door in the temple and is confronted by visions of Minerva and Juno, two members of that earlier civilization, each of whom wants him to do something different. Juno says to touch a powerful artifact that will stop the sun from firebombing the Earth and save humanity – but Desmond will die. Minerva says to let the catastrophe happen – a few humans, she tells him, will survive the fires and come to revere Desmond as a prophet and then a god.

Desmond quickly turns down godhood and touches the artifact. The apocalypse is prevented and he dies instantly. The end!

Oh, there's a brief stinger scene during the game's credits roll that shows Juno stepping over his corpse and saying something that vaguely sets up the inevitable sequel. But what Assassin's Creed III lacks entirely is any sort of denouement. After spending all this time playing as this character and wondering how everything fits together, you want to see the aftermath. For everything to end so abruptly is remarkably dissatisfying.

This seems to have been at the heart of the "Retake Mass Effect" group's complaints about their beloved series – even if they didn't really know it.

Unlike the linear Creed games, the Mass Effect trilogy remembers every little thing you do and alters the story accordingly, meaning that different players will have wildly different experiences. The group's big complaint was that the litany of choices they made during their five years of playthroughs were not reflected in the game's brief, one-size-fits-all ending.

But the solutions the fans suggested all revolved around more, not different, content: "new DLC (something long)," "closure as to the fates of the various races... and most importantly the fate of the crew of the Normandy."

Will Assassin's Creed fans feel similarly aggrieved following this week's release of the new game? Surely some of them will, but I don't know if it will reach such a critical mass. Mass Effect is a role-playing game; story is a huge part of why fans are attracted to it. But Assassin's Creed is an action game with a story wrapped around it, and so it's not difficult to imagine that perhaps many of its fans won't mind its abrupt ending.

Maybe that's why it's so brief in the first place – with all of the pieces that had to come together to make this colossal game, lavishing time and money on an extended finale wasn't going to happen if it only made a difference to a small group of players.

BioWare later told disgruntled fans that it was working on epilogue-style additional content that would incorporate their feedback.

Might Ubisoft be planning to do the same thing? Assassin's Creed III is a remarkably expensive undertaking; it's been in development for three years across six countries and hundreds of people. Ubisoft already plans to offer three downloadable story scenarios after the game has been released, a common practice these days to keep players involved and spending money on a game after they've completed it.

"I think Desmond needs to end," said Assassin's Creed III creative director Alex Hutchinson at a press event earlier this year, as quoted by Polygon. "Things that go on too long lack resonance. We're asking people to remember seven [sic] years' worth of story."

So ... was that it? Is there more? Desmond's story might be over, but it doesn't feel like an ending. After five games and six years, it deserves something on a grander scale than this.