I agree everyone should go watch this film, as it was really fascinating and a probably far more realistic take on living in space than most - the boredom, paranoia and drudgery were very effective - I feel compelled to stop discussing it here though in case I violate your no spoilers rule! I think I'll watch it again sometime, and I'll probably enjoy it more, not less, having read some of the discussion here and knowing more about it, and having seen all the twists of the plot already. Those are the least enjoyable and least important parts of the enjoyment of the film, and a focus on them omits all the other fascinating parts of this story (the repetition, the model-making as a way of escape, the corporation that controls his life, the convincing drudgery of space etc).
If you really don't like spoilers, don't click on discussions which purport to be about the film until you see it, or stop reading them as soon as the film is mentioned. That's really the only solution for you, and more effective than calling for no spoilers. Where did this recent obsession with spoilers come from?
A great story should not need the prop of plot-twists to be enjoyable - there are so many facets of entertainment which don't depend on plot (character, narration, allusions, themes, language, even setting and typography as here!). Stories like The Odyssey or Julius Caesar are not ruined by knowing the plot, because the pleasure is in the telling (and sometimes the retelling) and worrying over spoilers shuts down any sort of significant discussion of a film or story. To me shutting down all that discussion is far more damaging than any potential loss of momentary surprise when something happens you didn't expect.