Here is an exclusive debut trailer of Mass Effect 3. The video game will be the third and final game in the Mass Effect trilogy of video games developed by BioWare. The trailer shows a British soldier taking cover inside the ruins of Westminster Palace, commenting that casualties of a battle on Earth are in the millions, and all defenses have been either destroyed or are regrouping. This British soldier also takes a few shots with his sniper rifle at a target outside in the courtyard below. Video after the jump.