In the PlayStation Vita version of the game there is an interaction with Legolas, where he will say "They're taking the hobbits to Isengard!"
Repeatedly interacting with him will cause him to say the line as it was used in the 2005 remix by Erwin Beekveld.
Contributed by BTHRZeroX
During the cut scene at the end of the second level, "Weathertop", you can see behind Elrond the character Agent Smith from The Matrix series.

Both Elrond and Agent Smith were portrayed by actor Hugo Weaving in the Lord of the Rings and Matrix films, respectively. Both film series were also produced by Warner Bros.
Contributed by KnowledgeBase
At the top of Weathertop there is a wooden board protruding out over a puddle of water. If you have one of your characters jump off this board and into the water, you can hear an eagle's cry, similar to the Leap of Faith from the Assassin's Creed series.
Contributed by gamemaster1991