I absolutely loved how the invincibility of Achilles was visualized not by showing his skin to be stabbing proof, but by having him always stay clean even after a day of battle, and surviving by superior agility. It's my second favorite Wolfgang Petersen movie, and it deserves more recognition IMO.
What I liked about the Achilles angle is how it gave the myth of his invulnerability to weapons credibility. Early on the young attendant mentions it and he discounts it, insisting on wearing his leather armor into battle. When he's killed he's shown to pull out all the arrows except the one in his heel. Fires are burning and it's reasonable to assume that by the time he's found the only wound visible would have been the stone arrowhead still lodged in his heel.
