Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Dark, Uncertain, Conflicted
Although the narrator sometimes seems to be poking fun at certain characters (Annette's precious sequins come to mind), the predominant tone is dark and uncertain. As Emily wanders around the castle and the surrounding wilderness, "her eyes glance fearfully" about (2.6.59). Though she's scared of lots of things, we don't always know what's lurking out there.
That uncertain tone often gives way to a conflicted one, since we don't really know who to believe. Do we trust Em, who thinks the thing behind the veil is too horrible to reveal? Even the narrator flip-flops between marveling at some otherworldly spectacle and revealing something as not nearly as scary as it appears: "Had she looked again, her delusion and her fears would have vanished together…" (4.17.24). The narrator doesn't seem to know what's really scary and what's just mundane.