slow-motion it
If you make a careful frame by frame, slow- motion analysis of this footage, you will observe some significant wing distortion - which indicates the level of sink rate applying. I note that the crab was kicked off after the main gear touched and bounced not before- interesting...
Frame a datum line on the wing span just before touchdown and then do the same at max wings deflection and it is apparent that this registers as a 'harder' landing... Not that I am criticising, as I was not there and it is a short field...