Unfortunately, I didn't finish R2D2 in time, but I still got pretty far.
I successfully made the body, and some slight adjustments to the legs, but I was unable to extrude some of the faces on the head, as well as make the vents that appear along the body. I also would have had to paint the faces so that it looked like R2D2 (and some of the extruded faces would be more visible).