Soldiers do not wear plate armour at sea - it is a sure-fire way to drown.
The vessels portrayed could not possibly carry the number of men and horses stated, particularly considering the length of the journey and the amount of food and supplies they would need to carry.
When Elrond asks, "What troubles you?" his lips don't speak the line until a good couple seconds after it's heard.
When the orcs chase Arondir and his companions out of the woods, they inexplicably stop shooting arrows and futilely draw their swords before stopping at the edge of the sunlight. They only resume shooting once Arondir is out of range.