Well the jump scares and all were good, and the plot twist was cool too.
But why the kids did not ever see even a photo of their grandparents , that I don't understand. Also I watched this movie because I thought there was something supernatural in it, or the grandparents were in a cult or something. It turns out that they were just crazy old people doing weird and creepy things. And I personally didn't like this movie because a pair of old people are almost harmless and can be overpowered quickly.