Here's the R2D2 costume in practice

Being attacked by something less than a Jedi, the lid is solid armor.

It was a little difficult to see, and tough to reach around with the candy bag.

Being only a six year-old, he took a few spills and the costume suffered. It was tough to walk in, hard to see, and awkward. Design flaws noted, will improve next time. It lasted about twenty minutes before he fell and lay on the ground helpless like a turtle on its back. I righted him and got him out of it, then one of the neighbors put a cape on him & he continued hunting for candy happy as a pig.

Everyone who saw it in those glorious 20 minutes was amazed, and that's what counts.
Post-Script: you see the kid with the scythe in the photo above? I was walking ahead of him in the group last night when we passed a streetlamp. I noticed his shadow to my left growing long and passing me - a shadow of a hooded figure with a scythe, growing taller and more ominous with every step.
I wonder if anyone knows who Kenny Baker is....