The Road is an exact play by play walk through of the movie of the same name, and of the original book by Cormac McCarthy. Because I read the book and watched the film it was incredibly easy. I feel like someone that has not read the book, and has not seen the film would still find it pretty easy and perhaps be left unchallenged.
Not a bad interactive fiction adventure, but still it could be made more engaging. Perhaps add more about how the man is gradually dying or how the boy becomes more scared; add some tension or hopelessness as the player progresses.