Military 4

Lore & Background

In the lore implied by Factorio's progression, the military technologies represent a civilization's escalating response to the alien fauna that threatens its industrial expansion. Military 3 gave the player automated sentinels—turrets that could hold a line without a human operator. Military 4, by contrast, is personal: it places a weapon of sustained flame directly into the player's hands, acknowledging that no number of turrets can cover every gap in a sprawling factory floor. The Flamethrower itself is a compact, fuel-guzzling device. It does not deal the raw burst damage of a machine gun or the piercing reach of a railgun, but its cone of fire ignites multiple enemies simultaneously, applying a burning effect that continues to deal damage even after the initial flame passes. This makes it exceptionally effective against the swarming, low-health creatures that dominate early and mid-game encounters, and it becomes a go-to tool for clearing the dense enemy clusters that spawn around late-game resource nodes. Community lore often frames Military 4 as the moment a Factorio player stops being a passive engineer and starts feeling like a combatant. The act of sprinting through a conveyor-belt corridor, flamethrower roaring, while small alien creatures burst into orange flashes, is one of the game's most visceral and satisfying sequences. It is the point where the factory stops being purely a production puzzle and becomes a fortress you actively defend with your own two hands.

In Their Own Story

The alarm klaxon had been screaming for eleven seconds. You could hear it over the hiss of the steam pipes, over the clatter of the inserters, over the low thrum of the assemblers grinding out circuit boards. Three gun turrets had gone silent—two to small green creatures, one to a larger, faster thing that had simply walked through the bullet stream and kept coming. You dropped your stack of iron plates, grabbed the flamethrower from the crate by the logistics chest, and ran. The fuel gauge was full. The corridor between the oil refinery and the chemistry plant was narrow, just wide enough for two conveyor belts and a catwalk, and it was *full* of them—small, skittering, pouring over the walls in a grey-green tide. You squeezed the trigger. The flame roared out in a wide cone, orange and yellow, and the creatures caught fire almost instantly. They didn't die in one hit; they *burned*, tumbling across the catwalk, trailing smoke, their little bodies popping one by one as the fire damage ticked down. You walked forward, slowly, letting the cone sweep left and right, and the corridor cleared. Behind you, the refinery kept hissing. Ahead, the chemistry plant kept churning. The factory did not stop. You reloaded the fuel canister, checked the gauge, and ran back to the assembler line. There was still a stack of red circuits to insert, and the production chart was not going to fill itself.

Reader's Guide

Military 4 unlocks the Flamethrower, a handheld weapon that emits a cone of fire dealing damage-over-time to multiple enemies in its path. It requires Military 3 as a direct prerequisite, meaning you should already have Gun Turrets and Flamethrower Turrets in your arsenal. In practice, most players research it shortly after establishing a small perimeter of turrets around their early base, typically once they have a functioning science lab producing 2-4 science packs per second. The Flamethrower consumes Flamethrower Fuel, a crafted item that must be produced in a chemical plant (or crafted manually in a crafting grid). This fuel limitation is the weapon's main tactical constraint: you cannot hold a position indefinitely, and you must plan refills. In a pinch, the Flamethrower can clear a room of small enemies faster than a machine gun, but it will lose a sustained duel against a single high-health creature. In the broader tech tree, Military 4 sits between the turret-focused Military 3 and the long-range, high-damage Railgun of Military 5. It is not a prerequisite for any other technology; rather, it is a self-contained quality-of-life and defense upgrade. Many players skip it entirely in speedruns, but in a standard playthrough it is a comfortable, low-cost research that makes mid-game base defense significantly less stressful.

Did You Know?

• The Flamethrower's fire damage is a damage-over-time effect, meaning enemies continue to take damage even after the initial flame cone passes, which makes it far more effective against swarms than against single high-hea
• The handheld Flamethrower (Military 4) is a separate item from the Flamethrower Turret (Military 3); they share a name and a fuel type but have different damage profiles, ranges, and placement rules.
• Flamethrower Fuel must be produced in a chemical plant, meaning a player who wants sustained flamethrower use needs to have already set up an oil-processing and chemistry pipeline.
• In multiplayer, the Flamethrower's wide cone makes it a popular 'fun' weapon for cooperative defense, though its fuel consumption can quickly become a shared resource bottleneck if several players equip it simultaneously