spoilers-- in the films it was so eerie that . . .

the children committing the murders seemed to tie the family deaths to hobbies or activities they enjoyed.

for example, the first film showed Stephanie on the tire swing. Then she makes her family swing on the same tree; in the extended cut she actually uses her fathers body like a swing.

And Ashley loved to paint on the walls. So she used her family's blood for the "house painting."

When you think of those details and quirks being worked into how the kids committed the killings it is even more disturbing.