Soldiers of Fortune (Chaos Engine in the EU) is a run-and-gun overhead shooter. Sixteen levels (in four groups of four) await the players in the game. The basic gameplay is in an open air setting, with bridges across rivers and other features in the maps. The visuals are in a 'metallic and blue' style. There are six characters available in the game, each with different strengths and weaknesses, and different starting prices.

The setting is a steampunk Victorian era England. A time traveller on a reconnaissance mission from the distant future became stranded in the England of the late 1800s, and his technology came into the hands of the Royal Society, led by Baron Fortesque (based upon Charles Babbage), a grand inventor. Fortesque then retro engineered many of the futuristic contraptions, creating an entirely different, alternate timeline.

Baron Fortesque then succeeded in his greatest creation yet: the Chaos Engine, which was able to experiment with matter and the very nature of space and time. Unfortunately for the rest of the proud kingdom, the Engine then proceeded to become sentient, captured and assimilated its creator, and began to change the countryside for the worse. Vile monsters and destructive automata appeared everywhere, and even prehistoric beasts were resurrected. Telegram wires connecting the British Isles to the European mainland are cut, and any ship attempting to enter a British port is attacked. The British Royal Family, members of Parliament and a large number of refugees manage to escape across the sea, bringing with them many tales of horror. The British Empire is left in tatters, and the world in economic and political chaos. That lures a number of mercenaries on a potentially-rewarding quest to infiltrate the quarantined Britain, find the root of the problem and swiftly bring a full stop to it.