There are few weapons that can put fear into the heart of a foe like the Flame Cannon, one of the deadliest inventions of the Engineers' Guild. A volatile concoction of hot oil and molten tar is mixed within the Flame Cannon before air is pumped into the barrel; soon the pressure inside is tremendous and the barrel is almost ready to burst. At precisely the right moment, the Dwarfs place a burning oily wad into the nozzle and release the pressure. The mixture catches fire as it whooshes from the barrel in a leaping spurt. The burning oil arcs into the air towards the enemy ranks and, with a little bit of luck, lands in the middle of the foe, spraying boiling tar over them. For longer ranged shots, the Dwarfs simply apply more pressure, and the most experienced crew know exactly when to release the straining valve to achieve maximum distance. Those crews who misjudge this subtle balance rarely get another chance. Enemies struck by the Flame Cannons have their flesh melted off them in a slough, leaving only scorched bones and foul-smelling liquid that is best described as "goo". Even the bravest of those who survive, after seeing their comrades so gruesomely reduced, have been known to flee immediately.
↑Anti-Infantry: Anti-infantry units have an advantage against targets that are smaller than a horse. This advantage can be a damage bonus against small targets, superior weight used to smash through lighter enemies, or an explosive attack from range that effects a large area.
↓Weak Against Armour: This unit's attack can hardly punch through armour and is thus wasted on heavily armoured enemies.
Flame Cannons are devastating anti-infantry artillery, but are more specialized than any other Dwarfen artillery. Their downsides are their low range compared to other artillery (though they still outrange any missile infantry in the game) and not the most armor piercing damage. Against high armor units, they will struggle to be effective. This combined with the very high building investment required to produce them at all means Flame Cannons are a rare sight--in their niche, however, nothing can match them.
Flame Cannons are best against low armor factions that are likely to try and swarm a dwarf army like Greenskins and Norsca--or especially the undead Vampire Counts, with their hordes of cheap fire-weak chaff. Because the enemy is likely to try and surround you with hordes of infantry, the Flame cannon can destroy clumps of infantry when they get close. Also the Flame Cannon can be combined with a Master Engineer or two to increase its range, accuracy, and armor piercing damage. As with all artillery, Flame Cannons should be kept well out of reach of enemy cavalry and fliers, and should be placed above its blocking infantry on higher ground if at all possible, to minimize the chance of the cannon being blocked--or melting friendly troops.