It's a game about a gun. A Gryazev-Shipunov GSh-6-30 or some similar (wait for it) caliber. Something that fires 6000 kilo-sized bullets a minute and creates a death zone for several hundred meters around the target area and grinds down whatever it's mounted on within minutes.
I'm not so interested in guns, but it's fun to play make-believe sometimes.
So the game would let you control a Captain or somebody in charge of a team of let's say five engineers on a constant search for metals, minerals, gas and electricity to fuel, power, repair and operate the gun, vehicles to carry the gun around, places to mount the gun and robot armies and whatnot to fire the gun at; in short, searching for the cathartic moments when you get to fire the beastly thing.
The trouble from a development standpoint is just this game needs to look sexy AF. It needs production values high enough that you can feel the ground shift under the weight of the gun, feel the shockwaves as it tears apart the landscape, smell the hot steel and taste the sweat dripping of your loyal men and women, and see the shadows of the muzzle flash play over their oil-smeared muscles as they run, duck, lift, push and scream their way to blood-soaked victory, or see the pain in their eyes when their comrades fall.
But other than the most extreme demands possible of hard to come by skills and resources of which I have none whatsoever, it's a simple, light-hearted little project. I think I'd call it "The Thunder of her Gun" or something silly like that.