These are great! All that concept work - just for one character in the game.
It provides an inkling of the amount of design effort that goes into a production like this. Everything has to be concepted. Well, most things anyway. But even already extant elements we are familiar with such as pulse rifles and APC's need to be re-configured and re-designed, modeled in 3D, be optimised, tested, animated, have attachments function (which themselves have to concepted and modeled) and work as intended.
So much work goes into making a game that you just don't see or realise.