From the publisher:

In this expanded edition of RISK The Lord of the Rings Trilogy edition you will find:

• The detailed gameboard reflects a complete map of Middle-Earth including the Gondor, Mordor, and Haradwaith territories.
• Includes materials from the entire Lord of the Rings film trilogy.
• Additional Territory cards.
• Additional Battalions.
• Additional Adventure Cards.
• Alternate ways to play including special rules for alliance team play.

From BGG:

This game is essentially the regular Risk: LotR Edition with an additional board on the bottom and some new cards and revised rules.