I created this map a while ago before I really had any skills as a mapmaker. I had created Helm's Deep before in Stronghold 1, but could never get the balance right when playing as the defender. This is the result of my attempt in the Crusader version where you play as the attacker.
The ladder men are actually useful since you get them in so large numbers. Use the macemen to go up the ladders and attack the gate with your pikemen. The tunnlers are suppose to be the bombs that destroyed the deeping wall in the movei. You only get one battering ram so use it well.
If you don't know the story, read the Lord of the Rings books or at least watch the movie.