or its that shitty bug in M&B where up blocking is only on the client side and you are actually side blocking
http://tkc-community.net/forum/index.php/topic,16589.0.html They do have an unblockable but only 2 ppl have it the general publics only way to get it is if they know C++ and can find the variables for it which i doubt Vetro has the brains to do but i do agree with you on the client side blocking bug.
it's parsed in python the general code used for warband files, it works upon certain angular measurements
looking at the video the first two segments clearly show the attacks were unblockable, but the last two segments (slowed down 0.5) seem to be the block being let go
if you examine the first two segments closely you can see theres a certain angular measurement that goes through the block, which on TKC it states is needed to activate the hack