I don't get this. Did Reimu become a doll? Is that a "reaction face"? What is it?
That's just Reimu's ol' typical hungry face, good sir.
First of all, there's the sunken cheeks (the vertical lines on both of her cheeks), and the pursed lips (the * where her mouth is) that represent malnutrition.
Reimu is also shaking/wobbling constantly (shown by the dotted lines around her body) due to not having enough strength to go about. Then, there's the SFX "くー" (Kuuu...) that comes out of her stomach; it's a stomach growling effect.
As for her deadpan expression? Well...that's just how she is. LOL
Updated
MIDNIGHT!!Ugh...*Growwwl*Hang in there!*Growwwl*HUNGRY!!?IT'S...MIDNIGHT.Caviar...WHO'S...Reimu!?Foie gras on rice...Prawn Tempura...Can't you just have a Snickers bar or somethin'!?