Mass Effect 3 executive producer Casey Hudson has responded to players upset about the game's ending, admitting fans needed more closure and answers.

The statement comes days after the release of Mass Effect 3: Final Hours, a behind-the-scenes app/documentary. This revealed how Mass Effect 3's ending was once supposed to offer detailed information about the universe's origin, through a dialogue sequence at the very end of the game.

Casey Hudson, following ending backlash, said he and the development team now "recognise that some of our most passionate fans needed more closure, more answers and more time to say goodbye to their stories".

"Your feedback has always mattered," he stressed. "Mass Effect is a collaboration between developers and players, and we continue to listen.

"So where do we go from here? Throughout the next year, we will support Mass Effect 3 by working on new content. And we'll keep listening, because your insights and constructive feedback will help determine what that content should be."

"This is not the last you'll hear of Commander Shepard," Hudson said.

In a Mass Effect 3: Final Hours interview (posted on BioWare's forums), Hudson revealed that forthcoming DLC "would likely happen before or during the events of Mass Effect 3 - not after".

Mass Effect writer Mac Walters explained what the information-imparting ending once was, and why it was decided against.

"You get to ask a bunch of questions and you get your questions answered," he revealed.

"But then me and Casey talked and decided, let's keep the conversation 'High level' - give you the details that you need to know, but don't get into the stuff that you don't need to know. Like, 'How long have [the Reapers] been reaping?' You don't need to know the answers to the Mass Effect universe. So we intentionally left those out."

The ending of the game was not finalised until extremely late in the game's development, Casey Hudson revealed - "right up until the end of 2011".

"One night [Mac] Walters scribbled down some thought on various ways the game could end," Hudson shared, "with the line, 'Lots of speculation for everyone,' at the bottom of the page.

"In truth, the final bits of dialogue were debated right up until the end of 2011. Martin Sheen's voice-over session for The Illusive Man, originally scheduled for August, was delayed until mid-November so the writers would have more time to finesse the ending.

"One night [Mac] Walters scribbled down some thought on various ways the game could end with the line, 'Lots of speculation for everyone,' at the bottom of the page." Casey Hudson

"And even in November, the gameplay team was still experimenting with an end-game sequence where players would suddenly lose control of Shepard's movement and fall under full Reaper control. (This sequence was dropped because the gameplay mechanic proved too troublesome to implement alongside dialogue choices)."

Mass Effect 3's ending hasn't been the only source of fan backlash. An appealing squad member was reserved for Collector's Edition or paid-for DLC. This From Ashes squad member now appears to have once been part of the main game.

"In March 2011, [Mac] also faced a roomful of Mass Effect developers who expressed concern about hitting the promised holiday release date," said Hudson, revealing the decisions behind the game's delay to March 2012.

"After much deliberation, the CAT mission (or rather, the Prothean mission) had to be removed from the set of tasks. The missions would later be completed as post-release content."

A fan petition for the ending to be supplemented with additional information has now raised over $66,000 for the gaming charity Child's Play.

"We would like to dispel the perception that we are angry or entitled," the campaign's mission statement read. "We simply wish to express our hope that there could be a different direction for a series we have all grown to love."