I'm kind of glad that others had such a mixed, at best, reaction to this story so that it's not just me, as this seems like the kind of cleverly written piece that most people would love despite its limitations. Quick mood pieces that don't really go anywhere can be masterfully done and worthwhile. But I'm not sure this is a particularly good example of such a story. Waking up in the dark? OK, a basic fear situation everyone has experienced in childhood. Now, how to expand on it? The person turns out to be dead! Mind blown. Or not...
It's a well written piece that was a fun short read when I first came across it in one of the Best New Horror anthologies, but it does seem pretty limited, even for what it is. By contrast, Lovecraft's The Outsider raises issues of alienation and longing that seem more thought provoking in a similar very short space, only in that story, the protagonist climbs out of a cemetery as opposed to being perhaps suddenly trapped in one, depending on your interpretation of this story. The author's This is Now story is, again, a very simple piece, but it raises issues about changes and regrets in a small space that resonated with some readers. I suppose this story forces one to contemplate eternity in particularly grim terms, but that's almost as basic to horror as, well, being afraid of the dark, like the kid in the story. For some people, the technique and quick,hard hit of the theme will be enough. For others, it all runs a bit thin.