Rebalancing the shotguns by making them available earlier.
Small changes concerning balance, gameplay, or graphics.
New ways to deal with enemies, be it attack or defense.
Play it your way.
I kinda expected this to move the Combat shotgun to military 3? because mil3 also opens the way towards tank. EDIT Owh im stupid, it is already at military 3 :-)
Yes, military 3 by default unlocks the Combat shotgun. Which i found appropriate.