I say "superficially" because Outland is really more of a "man vs. the establishment" film. It looks like science fiction due to its location in a mining facility on Jupiter's moon Io, and because it has spacesuits, talk of zero atmosphere, and the analysis of a mysterious chemical compound — a recreational and often deadly narcotic being pushed by the mining facility's administrator, Sheppard — but its central conflict arises from Marshal O'Niel's decision to stand up to corruption, a conflict which could exist among the trappings of any genre and which is not necessarily best served by a specific one. I also hesitate to call it a "space western," for though it takes place along the lawless "frontier" of deep space, the mining facility is a corporate outpost, not necessarily a future Earth colony. Based upon O'Niel's wife's desire to return to Earth, we can assume that Earth is still a desirable and livable home. But these are debatable quibbles...
Outland seemingly duplicates much of the plot of High Noon: O'Niel's decision to interfere in the drug trafficking soon puts him on the defensive against a pair of hired killers, his wife leaves him prior to the showdown, his deputies are reluctant to help, and no one else wants to take his side against the criminals. These similarities, however, are also superficial, and altered enough to make their effects significantly different than those of their counterparts in High Noon. The hired guns, for example, have no personal grudge with O'Niel, no history with him at all, in fact. Their motive is strictly professional, and while the workers on Io do not want to interfere, it is not out of friendship with the killers or with Sheppard. O'Niel's wife leaves not because of any danger a potential showdown presents — indeed, she leaves before any such showdown is foreseen — but because her husband's work has meant tour after tour at remote space facilities, which she feels are not healthy for their son. (There are subtle hints that she understands what Sheppard reveals later — that O'Niel's reputation as a whistle blower has won him a string of unpleasant assignments, but she does not explicitly give this as a reason for leaving.) O'Niel's deputy, unlike High Noon's Harvey Pell, does not covet the marshal's job — he is a knowing bystander who has been silenced by Sheppard through bribery and a desire to live.
What is most interesting in the comparison of Outland to High Noon — and what makes the former ultimately less complex and challenging — is that the factors that made Kane's decision in High Noon so difficult have been altered so much that they are virtually irrelevant to O'Niel's decision. There is no longer a citizenry whose conflicting desires make the marshal's decision questionable. In High Noon, where it is explained that life in Hadleyville was dangerous and lawless before the Miller gang was stopped, some citizens want to help Kane, but are too afraid to do so, while others look forward to Frank Miller's return. In Outland, we never hear from the workers about the quality of life before or after Sheppard became manager, nor do we know their opinions about O'Niel's actions. Furthermore, the danger in Outland is not as generally applicable — while we can assume that anyone taking the dangerous drug could be at risk of death, we are not shown that everyone on Io is taking the drug. While both marshals decide rather quickly and instinctively what their decisions should be, O'Niel's decision seems far less complicated and his course of action seems much clearer: he is an officer of the law, therefore it is his job to stop the illegal and dangerous drug-running.
There is also in Outland a moment (my favorite in the film, as well as one of my favorite bits of Sean Connery acting) that is absent from High Noon, when O'Niel admits that his motives are personal. On the racquetball court, Dr. Lazarus asks him why he is standing up to Sheppard. "You know," she tells him, "if you're the kind of guy you're supposed to be, you wouldn't stick around. That's why they sent you here."
They send me here to this pile of shit because they think I belong here. I want to find out if...well, if they're right. There's a whole machine that works because everybody does what they're supposed to. I found out I was supposed to be something I didn't like. That's what's in the program. That's my rotten little part in the rotten machine. I don't like it. So I'm going to find out if they're right.
In High Noon, there is never as direct an admission from Kane that part of his motivation is personal. We can assume that Kane is not facing Miller entirely for the town's benefit, but we must decide the ratio of personal motivation to professional.
Comparing Outland to High Noon is easy enough to do — Outland borrows so much that it begs comparison. However, the comparison is ultimately unsatisfying and unfair, as it may lead one to feel that Outland is a failure at reproducing the complexities of the "original," instead of a success at becoming a different film entirely.
See also: The Dilemma of High Noon