I first played Tethered two years ago, and it must have been one of the first parser games that I played, so it took me a few days to get my head around; as a relatively short game, it was an excellent introduction to the genre.
In the introduction to this "interactive role play", as the title page has it, you play Charles, a mountaineer, but the main part of the game is shown from the perspective of Judith, his unfortunate partner who is left alone in the snow. The early puzzles see her exploring a cave system and deal brilliantly with the logistics of navigating around it. The descriptions of these caves are atmospheric and help prepare for the unexpected shift in tone that slowly develops as the story continues.
I was puzzled, but quickly came to realise what was beginning to happen; but as I reached the very final stages of the story I became confused again - what was really going on? I never guessed until I read the deeply poignant ending, with its ironic twist on the title. Tethered has all the clever plotting of a good short story, but it is one in which you actually have to act out all the things that Judith would do while sheltering in the caves, even ones which the reader knows would be a bad idea - and there's a very good reason for that. For this alone, I would hold it up as a great example of how parser games can be an excellent medium for storytelling and even have features that conventional storytelling does not.