I comented about it here
http://news.ycombinator.com/item?id=1250519 , that they "rediscovered" the role of the Dungeon Master from paper RPGs (and I think Neverwinter Nights and other computer RPGs might have something similar, though I don't know if it does).
Why doesn't he like the comparison? It's perfectly appropriate here.
Edit: I found this article http://www.destructoid.com/preview-sleep-is-death-player-mod... where he highlights the differences:
"The first and most obvious difference, the time constraint, essentially turns Sleep is Death into performance art. ". Ok, that's a point in its favor.
The second point is not valid "The computer screens that separated us gave the experience both a sense of tangible believability" as there are computer RPGs, though this might be a better / more freeform implementation (and that might be a killer feature)