Oberyn are you French? I'll put your emotional outburst down to Gallic impetuousness. Usually your posts are intelligent and free from ad hominem attacks. I feel safe from the charge of being "a fucking moron" when I say that I believe that many of the encumbered French knights were dispatched by archers, using long daggers and war hammers. These men would have had cloth wrapped feet. I'm sure the French knights were locally out numbered, exhausted and many were probably prostrate when dispatched with a stab through a lifted visor, under an armpit, or smashed on the helmet with a hammer.
I'll paste what I think is a fair summary from another web site.
Agincourt is the only well-known battle in history where a columnar attack struck a linear defence and failed to break it. The French did not use shields, as their plate armour was proof against almost any weapon powered by human muscle. I believe this was a mistake, as we know the arrowstorm caused them a great deal of trouble: the knights advanced looking at their feet, so the crown of their helms rather than their visors faced the arrows. The arrows probably produced disabling wounds such as broken fingers, penetrations where the arrow struck points of articulation covered by mail, and we know at least one noble was killed by an arrow in the mouth. At Flodden, 100 years later, the Scots gentlemen in the front line were protected by arrow-proof armour, but also pavises wielded by shield-carriers.
If an arrow did penetrate, its residual energy would be determined by the strength of the armour it had defeated. By 1415, a very few Italian and German smiths had just learned how to make plates of the size of breastplates incorporating at least some percentage of the strongest of the four types of iron crystal. Over the next hundred years they learned how to produce very thin corrugated suits of armour, which was as strong or stronger, but which weighed as little as 30kg. These would have been expensive for the richest nobles. By the same time, primitive gun-barrels could be mass-produced cheaply.
The English line was protected by stakes, that helped to break up the formation of attackers and impede cavalry [the sharp end was hammered into the ground, and then the blunt end sharpened]. Heavy cavalry, as always, had the advantage that they could close the range fast enough that they were exposed to few arrowshots, however horses were particularly vulnerable to any projectiles. All men-at-arms present [on foot] are usually technically described as "dismounted cavalry".
The BBC documentary suggested that mud produced by the type of soil on the field is good at forming an airtight seal when in contact with a necessarily smooth surface, and breaking this affinity might have been hard for those men-at arms who fell. The mud would have also reduced their surefootedness, especially if they were pulled over backwards by several varlets. Overall one gets the impression that many of the Frenchmen who got into trouble were probably outnumbered individually, however the fighting been men of quality was very intense and the king's beloved brother was killed in it. Agincourt seems to have been a battle that was a "losing game" from the start due that combination of circumstances that is always at the root of all accidental disasters, one of which was the very highly developed ideas of honour possessed by the attackers that so influenced their battlefield behaviour. This eventually became apparent the the French third line, after the other two had been fed into it. The scale and consequences of the disaster was enormous, given the number of important dead, to which was added consequent social and legal disruption in the aftermath. We can put this battle alongside Midway as an "incredible victory".