Fans of hit videogame "Mass Effect 3" will get "more closure" to the end of the saga in add-on software to be available free for download in the months ahead.

The studio behind the epic science fiction action trilogy made the promise on Thursday in response to a campaign by players demanding a happier ending.

"Since launch, we have had time to listen to the feedback from our most passionate fans and we are responding," said BioWare co-founder Ray Muzyka, who manages the studio now owned by US videogame titan Electronic Arts.

'Mass Effect 3: Extended Cut' downloadable content will provide "answers players are looking for while maintaining the team's artistic vision for the end of this story arc in the Mass Effect universe," he added.

Originally launched in 2007, the final installment in the "Mass Effect" trilogy was released on March 5 and snapped up by fans.

The games pit the main character, a male or female version of Commander Shepard depending on player preference, against an ancient race of machines called "Reapers" intent on wiping out organic life in the cosmos.

Allies made or friends lost in one game changes who is at the side of a player's character, and thus their options, in sequels. Players can opt to not import characters' reputations from earlier games so they can start fresh.

The trilogy was designed with varying endings to key plots to allow players to virtual feel the consequences of in-game decisions.

"We always intended that the scale of the conflict and the underlying theme of sacrifice would lead to a bittersweet ending," ME3 executive producer Casey Hudson explained in a BioWare website forum.

"To do otherwise would betray the agonizing decisions Shepard had to make along the way," he continued, in a reference to the heroic character whose choices and actions are controlled by players in all three titles.

A "Demand a Better Ending for Mass Effect 3" page at social networking website Facebook had logged more than 60,000 "likes" by Friday and a "@RetakeME3" account at Twitter had 5,954 followers.

"We have reprioritized our post-launch development efforts to provide the fans who want more closure with even more context and clarity to the ending of the game," Hudson said in a release.

Players were promised a cinematic epilogue providing insights to what becomes of their beloved characters.

"Extended Cut" will be available online for Xbox 360 and PlayStation 3 consoles as well as for versions of the game played on personal computers.