If D-Day had failed, Germany would turn the majority of their forces to the Eastern and Southern front. They could distract the invading forces long enough for them to at least create a nuclear device, if not a nuclear bomb. Then, they could detonate these devices at strategic points. neutralize the losses from Barbarossa and turn the invasion back to their favor. This may also stop invasion forces from the South. They would then vie for Air Control over London. However, America would still work on a way to invade Germany. My guess is from Scandinavia with a naval invasion of Denmark, seeing as the German Advanced Technology doesn't work very well in cold climates. Japan would not lose the Battle of Midway, as lots of aircraft will be poured into defending London and Britain. The cost of fighting Japan and Germany, along with propping Britain up will divert funding from the Manhattan Project. On the other hand, Germany would need the same funding so the max nuclear weapons they would use would be nuclear devices, basically crude bombs. Japan and USA will create a temporary ceasefire, and Japan will sweep through the Pacific and China and Eastern Russia with no major resistance. Russia will be shredded, and USA and USA-Britain will be the only powers left. However, they will eventually create a nuclear bomb, and bomb the Ruhr Valley and other industrial cities. They will also bomb Berlin, Hiroshima, Nagasaki, Tokyo, Manchu, now-German Controlled Kiev, now-German controlled Moscow, and other key cities. This would cause a whole slew of other problems but for now, USA wins.