Damir's More Defense

New ways to defend against biters, based on Damir's ideas: Scrap weapons, Spikes, Spiked walls, and the Acid tower.

Scrap weapons (Space Age)

The Scrap turret and handheld Scrap gun fire the usual scrap-recycling products as flying items. Both consume ordinary scrap at 20/s, preserving the 40% nothing outcome.

Rarer products hit harder: gears deal 6.25 impact damage, while low-density structures and holmium ore deal 125. Expected base DPS is 300, killing an unmodified behemoth biter in roughly 10 seconds of sustained fire.

Infinite Scrap damage research adds 90% of base damage per level, reaching 3,000 average DPS and roughly one second per behemoth at level 10. Damage scales linearly; individual kills vary with the rolls.

The turret holds 1,000 scrap, enough for 50 seconds of sustained firing. Open its inventory to load scrap by hand, or feed it with inserters. Its status shows the remaining scrap or explains when it is empty. The handheld gun automatically feeds from scrap in your main inventory. Both reach 25 tiles.

Research Scrap weapons after Recycling and Military 3 for 250 red, green, military, and blue science. Infinite damage costs 500 × level with electromagnetic science added.

Spikes

• Reusable floor traps that enemies walk over and ignore as attack targets. Each crossing deals 4 physical damage; a small biter dies on its fourth spike.
• Start with 100 damaging contacts of durability and lose one per hit. Their health bar tracks wear; construction robots repair and replace them normally.
• Infinite Spikes durability research adds 10 contacts per level. Full-health capacity is 100 + 10 × completed levels, with existing spikes benefiting immediately.
• A biter standing on a spike takes one hit; leaving and crossing it again causes another hit.

Spiked walls

Stone walls with steel spikes that deal the same spike damage back to nearby melee attackers. Enemies attack them normally.

They keep normal wall health and resistances, lose health only from incoming attacks, and receive no durability bonus from spike research.

Spike research

Spiked defenses unlocks both recipes after Military 2, Stone wall, and Steel processing, for 75 red and green science packs.

Infinite Spike damage adds 25% of base damage per level to both floor spikes and walls: 4 → 5 → 6 → 7, and so on. Durability research costs 100 × level and damage research costs 200 × level, using red, green, and military science.

Acid tower

• Sprays sulfuric acid using Factorio's flamethrower turret mechanics and a green stream animation with custom acid droplets.
• Covers a 120° arc at a range of 6–30 tiles; each splash affects a 2.5-tile radius and briefly slows enemies.
• Deals 6 acid damage at 25°C, 9 at 95°C, and 12 at 165°C, before resistances and damage modifiers.
• Reads the temperature of its internal firing buffer at impact. Hot and cold acid mix normally in pipes and tanks.
• Targets enemies and spares friendly entities.

Acid boiler

Burns ordinary chemical fuel to heat sulfuric acid to 165°C at up to 1.8 MW. Feed acid into either side and connect the front outlet to your towers.

The acid boiler supplies hot liquid acid. It is a separate craftable boiler; standard boilers continue to turn water into steam.

Research and compatibility

Research Acid defense after Flamethrower, Sulfur processing, and Advanced circuits, using 150 automation, logistic, and military science packs.

Requires Factorio 2.1.23 or newer. Acid and spike defenses work with the base game and Space Age; scrap weapons require Space Age.