American Conquest: Fight Back is a stand-alone expansion pack for American Conquest. It features five new nations: Germany, Russia, Haida, Portugal and the Netherlands, and 50 new units. In addition to new campaigns featuring the Mayas, the Germans, the Haida and the Russians, a new 'battlefield' game mode is available. The German campaign briefly chronicles the expedition of Ambrosius Ehinger and Georg Hohermuth whereas the Russian campaign concerns the Alaskan campaign under Alexander Baranov. The new Haida campaign is from the Haida point of view of the Russian expedition. The Mayas campaign covers details from the Spanish conquest of Yucatán.
A total conversion mod for the game was released in 2006, with patches and different versions released up until 2009, called European Warfare: Napoleonica that transferred the player back to 19th Century war-torn Europe during the Napoleonic Wars. The project was undertaken by Gexozoid (helped by the Hawks group and other associates) in 2007 and since then had a fairly active community on GameRanger and forums up until 2015. The Hawks Group recreated a vast database of historical battles that can be played in multiplayer by up to 7 players at the same time, sharing armies or fighting in co-op. It can still be downloaded at their original website or on ModDB. The Mod features over 200 new units and around 20 new buildings that range from a faction's Barracks to fortifications in the form of manned cannon towers and breastworks much like in Cossacks. 12 fully playable nations include: France, England, Poland, Austria, Prussia, Russia, Spain, Italy, the Ottoman Empire, Confederacy of Rhine, Sweden and the USA.
Achievements, for the most part, can only be gained in single-player Ironman games, on normal or higher difficulty, with historical nations started at 11 November 1444. Since patch 1.30 limited country forming (aka endgame tags) must also be active. Some achievements will require that you play as a released nation. Some achievements can also be earned while playing a custom nation. Four do not require the 1444 start date. All of this is noted in the table. 153554b96e