If it ain't broken, then don't Hyper Upgrade it...
Advance Wars 2 drops the Field Training option and introduces the basics in the early part of the Campaign. It's not quite as good as AW1, and might annoy vets to begin campaign like that, but it doesn't last long. In the Campaign, Sturm is back and now has an army to conquer Macro Land. This time, the 4 armies are united in driving Sturm back. There are 5 parts to the Campaign as I put it. The disappointing thing seems to be that the game is easier than AW1, although great challenges appear. I do wonder how much this contributes to experience though. If you beat Campaign, you will be able to buy Hard Campaign, which is not even close to AW1 AC, but it will still test you.
New to AW2 is the Neotank, which is more powerful than a Medium Tank and quicker too, but more expensive. Only adding one new unit to the game is kinda a letdown, but it doesn't mess with the balance of the units from AW1. There are 8 new COs, and the old COs have modifications. Some of the new COs are very cool and certainly some of my favorites. Also, they added a Super CO Power to go along with the CO Power that appeared from AW1. They are more powerful (usually) than their COP counterparts, but more expensive. Other modes are War Room, Versus, Design Map. Design Map allows you to create new maps (you can only save 3) which adds to the replayability immensely. Also there are limited new maps to the quota.
In the end, Advance Wars 2 is a fantastic game that does well to be a sequel to AW1, but some veterans seem to feel it a mere add-on. I feel while many elements are from AW1, the Campaign makes this worthwhile the title of a sequel.