Fire! Ogon! Feuer! is a set of free wargames rules for World War II Skirmishes. The author writes:
These rules are designed for use by both beginners and veteran players. Play can be quick and easy OR made more realistic and slower by adding advanced options.
Combat during World War II focused on volume of fire into a specific area combined with rapid movement of combat units. The weapon systems were poor by modern standards and there was a constant design battle between shell penetration versus vehicle armor.