(spoilers ahead! :P)
I came out of watching Moon thinking that Blade Runner, if you only thought a bit about it, covered the same ground, and in a better way. Moon is a corollary, a footnote to the world of Blade Runner.
And had the same feeling of fake-ish, exercise-ish, not-really-well-thought-to-the-end-ish that for example had Gattaca: there are a number of small details that are just left there hanging. They can be just forgotten and the main story is still there; or that's what I guess that the film makers thought. But nevertheless that makes it feel non-finished, not-taken-care-of. Like someone said "c'mon, the premise is good enough, don't mess too much with the details". But no, the result isn't good enough; interesting how that detracts from the whole feeling.
(I will forget about these details later, so better dump them here now: isn't it too easy to have those "filers" with the clones ready to be deployed? Is enough Gerty with those flimsy arms to ready and clean of hints an used room, or a whole base, before a new clone is awaken? Are clones really so easy to control for 3 years, do they never find about the extra towers? What are really Gerty's motivations, how come he's so straightforward and sincere and helpful sometimes and others so company-bound? C'mon, it can accept so easily that Sam is a clone but it can't say anything about the real-time communications? Also, is Gerty more like a person in which he moves and has a localized presence, or has it any more HAL-like control of the base? Generally it looks like a person, to the point of sometimes seeming absurdly limited because of it (it stands in front of the camera for a videoconference!), but in a couple of situations it looks like more in control than that... And, why keep at all the videos of the previous clones?)
But I kept thinking about the link Moon-Blade Runner. For at the beginning I only thought about the relationship in the purpose of the story, the problems portrayed. But there are much clearer, textual relationships. Replicants in Blade Runner were used (between other purposes) to mine distant planets; clones in Moon are used to mine the Moon. Replicants were persecuted in Earth; we hear that Sam is going to have "immigration problems".
Funniest of all: looks like the new film from Moon's director, "Mute Witness", will be somehow inspired by Blade Runner (as he himself says), and will sport a brief appearance of Sam Bell, "as an epilogue of his going to Earth". So: I'm betting he'll be "retired"!
Gotta watch again Blade Runner. It's hard to believe it was that wide, that thorough, that classy. I guess that comes from not having filler like clones playing ping pong.