As to whether or not Oppenheimer made a Faustian bargain, I think not. Oppenheimer was both a physicist and an American. As an American in the early 19405, he wanted to beat the Japanese and win the war, with as few dead American soldiers as possible. As a physicist, he wanted to use knowledge and technology to the United States' advantage, to win the war in the best way possible. Personally, I think the idea of killing Japanese people is wrong, but Oppenheimer would disagree with me on that. So by building an atomic bomb, he was helping what he thought was a good cause. He was very lucky that General Groves gave him so many resources, people and money for his project, but he didn't have to sacrifice his morals, so it wasn't a Faustian bargain