After watching the intro and playing the map a few times we can see our characters are after a capsule with a body in it. That body is actually our Original Tank Dempsey.
After our characters arrive at the castle there are zombies everywhere but no sign of the capsule,once they see the rocket go off Richtofen says "Our main goal is to bring back the rocket to earth no matter what". Even playing on solo as Dempsey he says something along the lines "Field Report:Dempsey 1.0 lost"
I was playing through the map and I noticed something on one of the monitors.
Yup that's Dempsey. So our main easter egg is to somehow bring him back.
But the questions is- What happened between The Giant and Der Eisendrache? Where are the other original "test subjects"?
Leave your theories in the comments,I love to read theories.