The egyptians had a very simple tactic: Archers rained arows over the enemies, the chariots entered in action and broke the ranks, after that infantry swarmed in and finished the job.
That was very eficient against poorly armoured and undisciplined foes.
With greeks (ouch!) that wasn't the case. Also some equipement became abolete (the kopesh won't pierce armour, chariots are in deep s... before a phalanx or horse archers and so on).