1.The 17 lbr anti-tank gun. Should of gone into production in 1940!
2. The British MGB (Motor Gun Boat). Go to love those little things; 115 feet long, 30 crew, 2 semi-automatic 6 lbrs (57mm), up to 4 Oerlikon 20mms (two singles, one twin), 40mm Pom-Pom, 2 dual Vickers .303s and four 1,500hp marine engines.
3. RADAR (Radio Auto Detection And Ranging); WINDOW, Chain Home Low, Chain Home, ASV mk III, H2S and H2X night bombing aids, Big Ben.
4. The Jadgpanzer IV.
5. The Panzershreck. The German copied the bazooka but went back to the original inventors design for the thing, making it much more effective.
6. Mulberry Harbours and PLUTO. Inspired ideas to difficult problems.
7. The MG42. Best machine gun of the war.
8. The Royal Navy. 'Nuff said, they rock!
9. Allied codebreaking and deception efforts. Fake armies, dummie harbours, signals intelligence and Enigma.
10. The Free French and Free Polish. No home left, country occupied, but still driven to fight to the end.
and one more for the road
11. The radar proximity fuse. The best 'wonder weapon' of the war.