More of what made the original game great!
The main feature is the ability to play the game until the end of 1953, giving you up to 18 years of game time to plan your world conquest.
My personal favorite is the addition of automated production sliders, relieving you of perhaps the most annoying chore of the original game. This allows you to not only prioritize building, reinforcements and/or upgrades, but also allows for automated trading.
Other changes include escort fighters being brigade attachments to bomber groups (instead of stand alone units), a new naval class of light aircraft carrier (provides additional air defense, but without a CAG), new traits for your commanders (including a history to allow you to keep track of battles won and lost), and several other minor additions.
The technology tree gives you the expected advancements of the cold war era, especially jet planes, but every tree has some additions to give you some added toys to play with in the post WW2 years.
The other main addition is the intelligence field. This allows you to send spies to other countries (not your allies) and gather intelligence on their forces and technology, as well as allowing you to perform certain actions to hurt their production, steal technology, raise internal dissent, or even assassinate ministers. Spying can have a penalty on your relationship with other countries. The big difference in game play is that you only have access to the exact number of units that your allies possess. You no longer get to have an instant and accurate update on how your whittling down of enemy air or naval forces is progressing, which makes for more realistic game play.
Graphics and sound are just like the original, so nothing spectacular, but perfectly good for this type of game. Game is stable on my system, although the game does experience some slowdowns when the action gets fast and furious.
To people who played the original, this is a great value at 20 bucks, and well worth getting for the additions. You get to play the original game with several years tacked on.
To newcomers, be warned that this game has a pretty steep learning curve. You need to be able to balance production, research and combat in order to succeed, and the less glamorous aspects of war such as logistics are more important than actual combat. But if you enjoy strategy games, stick with this, once you get the hang of it, better put a clock next to your computer, cause the hours will fly by.