Absolutely heart-wrenching. It'll deliver an emotional wallop to anyone, but if you've got kids it hits on a whole other level. The single-shot technique worked brilliantly and never felt like a gimmick. The acting is out of this world! As is the dialogue, cinematography, sound design... everything. The fact that I got a jump scare in the third episode, which was mostly two characters sitting in a room talking, highlights how tense the atmosphere can get.
It's a hard watch, but so essential!