I've just seen it and thought it was so powerful, particularly the backstory supplied only by the victim's videos.
One thing I couldn't understand is this. He killed his wife and then put her body on the floor of his car. He then put his (alive) children into the car and drove off to his workplace. He then killed the two girls and disposed of their bodies, and buried his wife.
But he left home at around 5.30 am (approx) - it was a 45 minute drive to work. His neighbour knew he left at that time - that's the time he checked on the CCTV. But how would Chris have time to do all that before anyone else got to work? If he normally got to work at 6.30 or so, surely others would be at work there, too?
I did think he probably killed the children in the house, when they discovered their mum was dead, which would mean he could kill them after his shift ended (as long as nobody saw them in the car) but he was pulled off shift, wasn't he, when the police arrived?
Or was there an extra day involved somehow? Shanann arrived home at 2 am, he left for work after 5 am, and she was reported missing by her friend that same day - is that right or was it the next day?