A Change in the Weather

For me the main obstacle was that certain puzzles require you to have a good idea of the 3-D topography of the game world. I'm not very good at constructing that kind of thing in my head, and the game, although decently clear, was not very good at helping me, and so there were several key actions that I never would have guessed without a walkthrough.

The parser is also limited, but that didn't really give me trouble.

What the game does do exceptionally well is build a sense of isolation and real dread out of what would seem to be an innocent scenario. The writing is excellent, not just in the sense of describing sunsets (though it does that too), but in that it maintains a subtle and seamless emotional tone throughout. Your friends are just across the river, but you nevertheless get the feeling that there is something serious at stake -- much more so than in most games where you are jumping off buildings and saving the world and so on.

My advice is to go in committed, spend some time, and try your best, but look at a walkthrough before you start to hate the thing. The solutions to the puzzles are satisfying but not worth banging your head against the wall for.