This is a very "nice" suspense/horror movie - with a satisfyingly good ending that explains and ties things together neatly. As with most horror movies - i went in without too great an expectation and was pleasantly surprised that i really liked it.
This movie may be a little bit too soppy or "nice" to be classified a real horror movie.
It does not rely much on jump scares. Actually it uses scares only sparsely - and instead goes with story and mystery. The roles of the foster parents are actually nicely done and acted. They are a lot less clichéd than countless other "typical foster parents in suspense/horror movies".
Special effects were alright but not too great - i would have loved to see more practical effects, because the CGI kind of made it look like a rather cheap computer cut-scene sometimes.
All in all - recommended - but not if you are looking for a real scare. Personally i d rather classify that movie as a fantasy story with scare elements.