Ease can be taken to mean many things while critiquing an interactive fiction.
Anchorhead is much easier to follow the plot comparing it to Colossal Cave. This is due to the structure of the story, with the plot development and descriptive scenes it allows for ease to be engrossed into the interactive story.
Disorientation is what caused frustration in Colossal Cave, and Landow said this about disorientation, “Is conceived…as crippling and disenabling, as something, in other words, that blocks completion of a task one has set for oneself or that has been set for one by others.” (Landow, 146) I never really felt disoriented with Anchorhead, just compelled to find the next right passage. I believe this was in part to the writing, but because of this the game seemed much easier.
So really, the ease of this interactive fiction can be related to the comprehension of the user in playing the interactive fiction. The greater the comprehension…the greater the sensibility of ease with the text.

Landow, George P. "Hypertext 3.0: Critical Theory and New Media in an Era of Globalization." Baltimore , MD : The Johns Hopkins University Press, 2006.