The Nazi Mech was to be an enemy that was cut from Splatterhouse (2010). Judging by the size, it might of been a boss monster. After the Nazis began to worship The Corrupted, the also built a large bipedal battle-mech that was to be used in World War II. When Rick visited the Nazi Hanger, he would be attacked by a Nazi Mech that possibly controlled by a spirit or zombie.
While no video of the mech has been shown, it probally would of used stomp attacks or shoot at Rick with its turret.