The basic construction is a black pullover from an old cheap store-bought halloween costume, and foam-core assemblies attached with velcro. There's a PVC 'backpack' that has mechanical arms with elastic bands that can flip up giving the General an extra pair of arms.
Step 1: Foam Core Assemblies
The foam core assemblies are sized for a child, but of course could be made larger for an adult. They are cut from paper patterns and most are bilaterally symmetric. Some sections are pre-painted and 'weathered' with dilute black tempera paint to give shadowed 3D effect. I used hot-glue to assemble them, but other glues are fine. When dry, they are aligned onto the body-suit with velcro on the assembly and the suit. The suit velcro should be sewed on (or stapled if you're hasty).