Here are a couple of wartime photographs showing the nose gun position and the belly gun position in this aircraft. Don't think I would've wanted to be in those spots with a Spitfire shooting at me...
Here's a YouTube video of the only flying example of the He-111 left in the world.
Apparently this was an exhausting plane to fly. It required constant input from the pilot to keep it on course, the cockpit was very noisy from having the engines on either side, and all that plexiglas made it kind of a hothouse. Still, a really interesting design for its time.