The player assumes the role of James Chase, an American who has volunteered to serve as a fighter pilot in the Royal Air Force starting in May 1940.

The player's principal opponent is the Luftwaffe, in particular the Battlehawk's counterpart, the elite squadron of top German pilots known as Nemesis (similar to the real KG 200), commanded by Oberst Krieger.

Although most of the gameplay is in the air, certain parts of certain missions are set on the ground and the player must use anti-aircraft weaponry to shoot down enemy planes.

The first part of the twelfth mission is in a turret of a Boeing B-17 Flying Fortress bomber, and the player uses machine guns to fight incoming fighters.

Secret Weapons Over Normandy is notable for the presence of several prototype designs that never flew in combat, or were used in small numbers, among them the XP-55 Ascender, XP-56 Black Bullet, Chance-Vought Flying Pancake, the Junkers Ju 390, and the Daimler Benz C. Also present are several German weapons projects that were either never completed or failed to make a significant impact on the war, such as the Mistel and the Wasserfall missile launcher.

It also features the unlockable TIE Fighter and X-Wing starships from the Star Wars universe in the game's instant action mode.

[6] The game's soundtrack, composed by Medal of Honor's Michael Giacchino and performed by session musicians of the Northwest Sinfonia, was released as a two-CD set by La-La Land Records.