That's my one concern with Black Phone. We saw it the other night, and there's not much to pull from outside of The Grabber's house. There are some pretty decent jump scares that they can try and recreate, but the sets might tend to look a little bland. Lots of basement walls, beige 70's style house interior.
I'm sure they'll end the house with a team-up assault from both Freaky and Black Phone characters. So, at least that should be pretty cool.