Engineering: Far better then the anyone else.
A-Bomb: No one else was able to make one during the war.
Logistics: We fought and won a two front war with each front on the other side of the world (Hitler could not even cross the Channel), oh yea we also supplied the Russian Army.
To be continued....
Fire for effect! Germans actually feared American artillery more than the Russian Arty. While Russian arty was used in great volume, It was most effective in pre-planned fires ast the start of an offensive operation, or as part of a defensive plan, but was not very flexible. American artillery, while not achieving the volumes of fire that the Russians could produce, was accurate and could respond quickly to German action on the ground in support of any American with a radio or field phone.