This is the Mission Pack for the original Rainbow Six, and you do need the original Rainbow Six to play it.
The game mechanics, method of movement, and so forth are the same for this expansion as it was for the original Rainbow Six. I am going to concentrate on what additions "Eagle Watch" brings to the Rainbow Six game, but if you want to know more about the original game, then please check out my review for it: Tom Clancy's Rainbow Six
This mission pack brings you 5 new missions, and they start immediately after the conclusion of the first game. They take place in many interesting locations. You will be battling terrorist (Tangos) from India to the Capitol building in D.C.
This game also gives the player 4 new operatives to choose from when setting up your teams. If you read the Tom Clancy books, then the names of these operatives will be extremely familiar to you.
Last but not least, the game gives you 3 new guns to use against the terrorist scum. They are the following: Heckler & Koch G36K, Heckler & Koch G3A3, and IMI .50 Desert Eagle. These new guns are very effective, especially against Tangos that use body armor.
I think the only gripe I have for this game is that the graphics are still mediocre. You would think that the expansion would have made an effort to improve the graphics from the original game, but sadly that was not the case.
If you liked the original Rainbow Six, and want some more tactical combat action, then "Eagle Watch" will satisfy that craving for you.