Well there isn't a lot of feedback I can offer for the demo given it's extreme brevity, I believe it took me about 10 minutes from the (lovely) opening graphic to the completion of what is currently available.
However I do have to say you've got the right mix of creepy and childlike, not that children can't be creepy, in fact that's a pretty well established trope, but I mean that you have the lighter elements one tends to associate with childhood and then you've layered all those fears that children also inhabit on a daily basis. Children are much more susceptible to abandonment and loneliness than adults simply because they are so much more reliant on their parental/guardian figures to provide a safety net, something adults need to and generally do provide for themselves. The feeling of fear and that stomach gnawing doubt that creeps through the game play with each transverse of the supermarket is done very well, and I am really looking forward to how you continue that trend as later sections of the game are added. Though I would caution against ramping up the suspense too much, there is a tipping point at which people's ability to empathise and relate becomes nonsensical and you lose that feeling of connection which is quite vital in a game of this type.
I adore the careful story elements you've added, the alarm in the supermarket, the fact that every shelf has a dialogue response they show an attention to detail that bodes well for the expanded version. It shows you have fleshed out the world in your head first before you ever opened up the engine to create it.
Speaking of the shelf dialogues in the supermarket, it should be toilet paper not toilet papers, which is one of those terms where plural and singular use is the same, like sheep. Also in the grocery section, not the frozen foods, you've got the dialogue set to come up no matter what direction you are facing, which doesn't quite work, it should be set to only appear if the character is facing the shelf. Also the lady with the black hair, pinkish top and jeans who wanders around near the bread doesn't say anything when you interact with her in that first section where everyone has a response. Also the two lowest right freezers in the bottom middle row, not the one against the southern wall, don't give a response to the contents when you interact. It's odd given everything else does.
One thing I would say purely technical, the self extracting exe is set to extract to a programme directory, that generally causes issues for some people, you may want to redirect it to either pick up the directory into which is was downloaded, or the classic c:\games.
Anyway I'm looking forward to seeing where you go with this and especially what it is on the other side of her bedroom door.