Units look better. Sauron and Glaurung are now included. Unit strengths heavily modified. All terrain is now more varied. Anywhere where I could justify it according to the books, I added forests, hills, and plains.
Some rivers are now impassable except at fords.
Likewise, some mountain ranges cannot be crossed except at designated passes. Gondolin has been made larger and more powerful. This was done after further research demonstrated that I had misjudged the size and military power of Gondolin. Girdle of Melian implemented differently. It is no longer a Wonder and is now much more powerful.