One can argue the American Revolution of 1776 as being a 'Civil War' but the War of 1812 was not. However the War of 1812 can be thought of as a 'pre-world war' or WW -1.
The War of 1812 in a global point of view was simply another theater of the Napoleonic Wars. Like WWI and WWII the United States was 'late' for WW-1, since it started in 1803.
Ireland, Cross of St. Patrick - Scotland, Cross of St. Andrew - England, Cross of St. George
The flag of the United States was 'stripus maximus' with 15 stripes. After this war the US flag would revert to only ever having 13 stripes. The flag of the UK was in its modern form with a new element since the American Revolution. During the American Revolution the UK Union Flag was based on two crosses - St. George and St. Andrew. But during the War of 1812 the Union Jack was composed of a trinity of three crosses. In 1801 the cross of St. Patrick was added which is quartered into four small thin parts around the corners.
The United States was an ally to France. But since 1803 the British and French 'drafted' several other nations. These nations like the United States often switched sides. It can also be painted as another French and Indian War. However most of the Indians were on the side of the UK, and the US was ally to the French.
The world wide war battles were fought all over the globe in Asia, India, Africa, and North America. Navies also fought in the Atlantic, Pacific, Indian Oceans, Great Lakes and the Mediterranean Sea.
Nations involved in WW -1 (War of 1812/Napoleonic Wars)
1803-18151. Poland (Duchy of Warsaw)
2. Italy (Sicily, Tuscany, Sardinia, Naples)
4. Netherlands (Nassau, Holland)
5. Spain (bitterly divided)
7. Turkey (Ottoman Empire)
9. Germany (Rhine, Brunswick, Hanover)
10. Prussia (wiped off the map after WWII)
17. Countless Unrecognized Native American Nations