tl;dr: the vast majority of what he calls a broken hitbox is just him getting hit in his legs or him standing in a clearly visible shockwave
Intro 0:00
Projectiles through wall 2:27
Fire through wall 2:46
A few hitboxes 3:42
Generous fire 5:30
Actively swinging 7:12
Broken Giants 9:04
Weapons extending forward 10:22
Refuse to hit 10:44
Grab teleporting 12:32
Grab hitboxes 14:04
More hitboxes 16:11
Bandit Knife 20:48
Even more hitboxes 21:36
Mimic grab 22:18
Velstadt slam 23:11
Fume Knight slap 23:28
ADP 24:01
DS1 and DS3 27:05
Summary with examples 28:38