From the manual:
Besides being Windows-95 native, Longbow 2 has an array of new capabilities - while preserving elements you know and love from the first Longbow.
The game has two new dynamic campaigns with a wide range of mission objectives - the first campaign simulates a full-scale war game at the National Training Center at Ft. Irwin, California. [...] A second, in-depth campaign occurs in Iran and Azerbaijan, where you handle a realistic conflict dealing with the Caspian oil resources.
Longbow 2 allows you to pilot the AH-64D Longbow Apache (and the AH-64D without the Longbow radar), the OH-58D Kiowa Warrior scout helicopter and the UH-60L Black Hawk utility/transport helicopter.