I always thought the same way ragingfire. I never understood how so few men could defeat so many trained orcs and such.
They reload all the time these days, that way you can have the slow-motion shots of the empty clips (always two because since "The Killer" you gotta have two guns) falling to the ground.
Well in the books, the orcs get caught between the hammer and the anvil...twice. First the onslaught of the Rohirrim breaks their lines from one side...then as the evil forces reform and advance again...the men of the city rush out to catch the orcs in between...then, when it looks like all hope is lost, the "corsairs" are coming up the river to aid the orcs, out comes Aragorn, not with the army of the dead, but with all the men of Gondor that were on the coast...catching the main host of the orcs between the men of the city, the Rohirrim, and the people from the ships. It was at this point that Aragorn and Eomer meet up again, though all the hosts of Morder lie between them. I'm such a huge dork.
and also...in addition... the orcs were not so highly trained...either on the Plains or at the Gate. The only thing keeping them fighting at all was the will of their "Overlords"...the Witch King(Head Nazgul) who was slain on the Plains before the city and Sauron himself in Mordor... When the Battle for the city was going...even with the 3 seperate armies hitting them...they would have still overcome the defenders if the Witch King hadnt been killed by Eowen. and the army led by Aragorn at the Gates of Mordor would have been annihialated by the forces of Mordor if the Ring hadnt been destroyed when it was....when that happened the forces of Mordor were so demoralized they couldnt fight and for the most part ran. Im an even bigger dork.