This trophy is basically just a platinum for the DLC trophies. You must kill Hitler/His Double in the following ways: (Click the bit.ly link to visit the associated guide for the death)
* Shooting him.
* Dropping a bell on him. (http://bit.ly/VMl7Yc
* Blowing up his car via a weak spot. (http://bit.ly/1wmBsDU
* Blow him up using barrels. (http://bit.ly/1l4mfTb
* Blow him up using a chain reaction. (http://bit.ly/1tshuUH
* Shoot him while he is in his car.
* Blow him up using a grenade.