The studio behind hit videogame \"Mass Effect 3\" on Monday responded to an online campaign by fans for a happier ending to the gripping science fiction action trilogy. \"There\'s been a lot of discussion and debate about the conclusion of \'Mass Effect 3\',\" videogame executive producer Casey Hudson said in an online post on the BioWare website forum. \"We always intended that the scale of the conflict and the underlying theme of sacrifice would lead to a bittersweet ending,\" he explained in the studio\'s first and only response to the campaign. \"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 decisions 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 42,000 \"likes\" by Monday and a \"@RetakeME3\" account at Twitter had 4,528 followers. One fan took the campaign even further, filing a complaint with the US Federal Trade Commission arguing that game-maker BioWare and publisher Electronic Arts weren\'t honest about how the trilogy would end. The final installment in the beloved \"Mass Effect\" trilogy was released on March 5 and snapped up by fans who were then thrust into an epic battle for Earth. The trilogy launched in 2007 meshes action and interactive storytelling that lets players shape which direction the saga takes, with decisions changing the outcomes of situations and the fates of in-game characters.