While it's not the only criteria I look for (far from it) but for me one of the hallmarks of a great MOC is it doesn't look like LEGO at first. I know this seems at odds with a love of the bricks but let me explain. One of the things I find most fascinating about building with LEGO is the fact that is is transformed into something else. Each element is like a stroke from a pencil, a pixel on the screen or a thumbprint in clay. Individually just fragments of a larger idea, but It all comes together to become something else entirely. And when is it is so successfully transformed that those individual fragments disappear altogether, it's magic. This alley scene by builder LEGOMINDED just looked like a photograph of an urban scene from the thumbnail, I almost scrolled right past it. Beautifully conceived, built and photographed...transformed.