First of all you get a whopping 48 historical scenarios that cover the battles of Cedar Mountain, 2nd Manassas, and Chantilly. In these battles the force under your direct command will range from a tiny 3 regiment brigade of 800 men, all the way up to an entire army of more than 60,000 men. Most of these scenarios have branching decision trees in them that introduce variations with each replay that range from very subtle, to extreme.
Even if you play a scenario twice and it takes the same branch, the game will still play differently because to the personalities of the AI commanders. That’s right, I said “personalities”. Each and every commander in the game has a personality that is rated for such things as initiative, ability, etc. Therefore, a commander’s actions will be influenced by his personality. A timid commander will tend to hold back, while an aggressive one will take the battle to the enemy, which is all well and good if he has mad skills, but that is nothing quite as bad a an aggressive leader who is incompetent, and believe me, you will find some of those in the game (General Banks for one).
So, after playing, and perhaps replaying all 48 historical scenarios, you still have Open Play to explore. Open Play is just that. First you pick a battlefield from one of the eight maps that come with the came. Next you pick what type of battle it will be with options ranging from meeting engagements, defensive, offensive, or set-piece battles. Then you pick what order of battle to use such as Cedar Mountain, 2nd Manassas, etc. (side note: there are already several custom OOBs created by users that you can also download and enjoy). Next you select which particular commander you want to be, and this can be anything from the commander of a single artillery battery all the way to army commander. Finally you decide how long you want the battle to last. Then the game will start with you units placed at variable (yet sensible) locations on the map and the battle commences. There are literally thousands of possible combinations for open play, and you will most likely never exhaust them.
In conclusion, for your $40 bucks you not only get an outstanding game, but it will keep you playing for many months, if not years to come. Sounds like a pretty good deal to me!