The Spear of Destiny is the spear that was used to injure Jesus Christ when on the cross. In real life, Hitler's paranormal division attempted to acquire the Spear of Destiny since Hitler believed that possessing the Spear of Destiny would help insure Nazi victory.
Spear of Destiny actually takes place before the adventure in the original Wolfenstein 3d.
There is another 2 Spear of Destiny games, which had a different graphics, sounds, animations, and sprites
The death sprite of Trans Groose (Floor 5 boss) is identical to Hans, despite the green armor