Hearts of Iron III: Secret Weapons of WWII DLC on GamersGate

[Johan]

There were technical compability problems with it, so will not be released at the moment.

 

[Darkrenown]

This is not easy to represent those stuff ingame as a gameplay fun unit. And Germany already got 3 weapons (+ the french weapon if they act historically) so I didn't want to give them too much. Here we have 5 axis weapons and 4+1 allies-comintern weapons.
I was surprised that Soviet Union didn't make that much secret weapons (or too secret for me to find them). Besides the multi-tank hoax "he doesn't need to turn, just point it into the direction of Berlin!" I found nothing relevant in this timeframe.

How about the K7 bomber? There's also the Russian anti-tank dogs, and their screw-drive system.