It's not too short to develop a creepy atmosphere, though. The illos are excellent, and the details of how unsettling doll 'life' is to an outside observer are excellently done. Sleator has taken the effort to imagine how repulsive the dolls would seem to a girl become the same size as them -- the books she has given them seem like dirty cardboard, and the 'father doll' constructed out of a blurred cotton face and pipe-cleaner limbs looks fairly horrific when it's six foot tall.

The story doesn't make it absolutely clear whether the unpleasantness is from the girl or the dolls (although it's very clear that something is affecting her family), but my reading is that Vicky's disappointment and frustration in getting a grotty old doll's house makes her spiritually vulnerable, and something rather nasty gets in.