lmao @ the Persian army being 3 times as large ... modern estimates reveal that logistically Darius couldn't field that many men in even an open field pitched battle, it simply wasn't possible to mobilize that much of a force to a single area ... here is a battle where the enemy is well over 3 times as large
http://en.wikipedia.org/wiki/Battle_of_Firaz
and you're still comparing bronze equipment to WOOD (Persians were still using wood although they did use iron swords) ... the Persians hardly wore any armor at all ... and Darius (who was running more than fighting) tried to use chariots against the phalanx, which proved to fail ... they were fighting a modernized greek army with new tactics developed by alexanders father ... you're simply lying if you don't believe they didn't have superior infantry and superior overall cavalry ... Persians really only had archers over them and a couple of hundred of chariots ...
and the death story of Darius is just a myth, unless he came back from the dead and started writing letters to Porus ... like I said, he used his fathers military to defeat a declining Persian empire ... he was just a semi-barbarian warlord who destroyed a declining persian empire ....