Okay, as near as I can tell, the one on the right is 100% movie accurate on the exterior. This means the legs, arms, bottom, and all faces of the cube are exactly as they appear in the movie. The inside is mostly improvised for stability, save for a few pieces that i glimpsed in this video. Colors are mostly restricted to black and light grey; the Micro Managers always appear in weird lighting so it's difficult to tell if any of the grey is actually supposed to be dark grey, but I'm pretty sure it was all light.
The one on the left is the nearest you can get to movie-accurate with existing pieces. (Even then, the rendered image is outdated; I didn't notice one of the flaws until it was already well into the render and I didn't want to spend the time waiting for it again.) The only notable changes are:
- The finger tips are metallic silver viking horns instead of light grey Chromastone spikes, which have only ever been fuchsia
- The hip joints are dark grey, instead of the movies black, which that piece as never come in
- The slotted 1x2 cheese slope on the front is dark grey instead of light grey, as that piece has never come in that color
Otherwise, they are identical. The hatch on top opens, but there's nothing notable inside, as my main focus was on accuracy on the exterior, not playability.
I have included the .lxf file so you can tinker with it or take a good look at it, since I haven't exactly given the best look at how it was done. I've ordered the necessary pieces to build the one on the left off of Bricklink; if you intend to do the same, I will warn you that the piece that connects the arms and legs to the body is fairly rare; I couldnt find any shops that had more than one in stock, so I would build most of my purchase around those shops if I were you, for convenience.
I wasn't sure if this went here or in LEGO discussion since I didn't really do much creative work here; I just took a stab in the dark.