In that demo, they had all weapons unlocked for the medium body, just for demonstration purposes. If you look at the weapon menu, you can see all of the heavy weapons available.
Hjammerdiem (SRM-1216) is the heavy shotgun, Mossington (XM-1014) is the medium shotgun.
I wonder if the Mossington will be semi-auto, though. The 1014 is, after all.
moving is the only option if you want to live, shooting and hitting while moving will prolong that experience, standing still will only make you die, movement is what they've built this game around
Objective based gameplay is what they build the game around.
Now many objectives require you to stand still for a while.
See where I'm getting at?