The American Civil War also saw the introduction of aerial surveillance, factory-produced munitions on a large scale, mass transportation of personnel and materiel, long-distance communications via electronics, more pervasive use of photography, canned rations, the origins of modern military medicine, total warfare against enemy infrastructure and support mechanisms...
The Napoleonic Wars were the zenith of thousands of years of combat procedure and its evolution. The American Civil War was the bloody birth of something altogether new. Everything since then, including arguably the use of nuclear weapons, has been refinement of what came about during those five years.
Adding to your post the ironclad gunboat USS Cairo (the remains of which are on display at the Vicksburg Battle Field) was sunk while on duty on the Yahzo river near Vickisburg by a electrically detonated mine. The first vessel sunk in such a manner.
Adding to your post the ironclad gunboat USS Cairo (the remains of which are on display at the Vicksburg Battle Field) was sunk while on duty on the Yahzo river near Vickisburg by a electrically detonated mine. The first vessel sunk in such a manner.
The Civil War was the juncture of Napoleonic tactics with modern, accurate weaponry. The result was a bloodbath.
World War One was similar when post Civil War tactics ran into the Maxim machine gun.
Add to your list: the first effective submarine, aircraft carrier and railroads used for rapid transport of troops & equipment!
Aircraft carrier, USS George Washington Parke Custis (1861):
Submarine, CSS Hunley: 
Civil War railroad transportation: