That's Mass Effect. FO uses 2mm slugs. The crank is used in the hang fire animation. When it misfies, you wizz the crank around a few times, iirc.
That's right. The side magazine is supposed to be filled with 2mm slugs, but like ME is considered to be in infinite supply. (For the Fo3 Gauss that is, in the earlier one the energy cell and slug were part of one self contained ammo unit)
The crank I think might be similar to the forward assist on an AR, something you use when things aren't seated right like you said. However, another explanation for the crank is that it's a DeGausser for the Gauss gun. If you ever look at your monitor or your TV in detail, you'll find an option to DeGauss the TV, which basically releases built up static electricity and magnetic fields in a crackly sort of way.
It's possible that built up magnetic fields could effect the gun's own performance in using magnets to propel their projectiles, and would effect it more adversely if the rifle was in poor condition. Therefore the crank is a manual DeGausser to remove the unwanted magnetic field.
It wasnt overpowered in Fallout 3. Its DPS was awful and wasnt worth using unless it could one shot kill the target.
Well, it was overpowered in a way. Its knockdown effect allowed you to essentially juggle enemies. Just keep plugging them while they're down and the effect will keep knocking them down. Of course, the victory rifle did the same thing, but MFcells are cheaper and more common than .308, and the Gauss Rifle has a higher chance of knocking down enemies than the victory rifle. And being an Energy weapon, it fills the victory rifle's niche for energy weapons users, as well as filling the sniper role in general.
One slot for armor, one slot for helmet.
Don't forget the glasses/face items. I bet that's what that mask is. I hope there are different types of masks too, like a full face mask, or a mask with goggles, so I can truly play Fallout: STALKER.