In Cirith Ungol, there is a secret room with Uruk-hai manning watchtowers. If you are spotted, a red exclamation point appears above them and the Metal Gear alert chord plays.
If boss disguises is turned on, Shelob has rollerskates on. It counts as a shout out and a call back
LEGO The Hobbit
There are several references to The Lord of the Rings (books and movies). The "Po-tay-to" is a quest item, for example, and there are several quotes and LOTR characters that have no relevance to The Hobbit.
There are multiple side missions that feature the player character fighting a story boss’ mother, such as Goblin-in-Law and The Memory Arena. This is a reference to Beowulf, one of the main inspirations for Tolkien when writing The Hobbit, where after the titular Beowulf slays the monster Grendel, he faces the wrath of Grendel’s more monstrous mother.
If Tauriel has the sprint-boosting Mithril Horseshoes equipped and her dual daggers out, she will ''Naruto'' run.