Phallanx is not just long spears. They have to be all positioned forward forming a sort of wall of spears. The macedonian phalanx is just longer then the normal one.

People back then were much shorter then today so a 6 foot long spear would not be a dart. IT woudl in fact be a spear. If you look at any ancient greek aggio you'll see that the spears they used were long at all. Not anywhere near to form a desent wall anyway. they were kind of like the Triarii in the game.