This worked. The tension, particularly in the first part, was excellently sustained by careful and minimal use of tension and atmosphere-inducing music allowing silence to play its part. The updated scenario was effective (not token feminism as some reviews suggested) and it was wise not to go into any detail about how the invisibility worked.
I also liked the way that, before the succession of very effective plot twists, the possibility of it all being in her mind was suggested – and the film gave a darkly powerful illustration of the terrors of being stalked which were more than applicable to modern times, even though modern social technology was not a part of the film which it would/could have been if it was made, say, a decade later.
Moss was very fine as the heroine with a nice suggestion at times of hysteria that never went OTT. A good effort.