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Enemies are creatures that want to harm the player. They are the native inhabitants of the extraterrestrial world in the form of arthropods living in organic nests, coexisting with each other peacefully. They are encountered in three species: Biters, Spitters and Worms. The species are further distinguished in four (or three in case of Worms) stages of growth and thus strength.


Enemies are directly connected to the following achievements:

It-stinks-and-they-dont-like-it-achievement.png Znečištění se jim nelíbí

Spusť útok nepřítele vlivem znečištění.

Steamrolled-achievement.png Parní válec

Znič 10 hnízd.



Biters are one of two main antagonists in the game. They come in four sizes: small, medium, big and behemoth. In the beginning of a game, there will only be the small ones. With increasing pollution, they will become bigger, related to the enemy's evolution. As common sense may suggest, their method of attack is a straightforward charge to "bite" things.

Picture Name Info
File:SmallBiter-anim.gif Small Biter Weakest of biters, can be easily killed with a pistol.
  • Health: 15
  • Damage: 7
  • Attack Speed: 1.7 /s
  • Damage Type: Physical
  • Range: 0.5
File:MediumBiter-anim.gif Medium Biter Stronger and slower than the small biter. Can pose a problem for and even kill weaker players.
  • Health: 75
  • Damage: 15
  • Attack Speed: 1.7 /s
  • Damage Type: Physical
  • Range: 1.0


  • Explosion: 0/10%
  • Physical: 4/10%
File:BigBiter-anim.gif Big Biter Dangerous, resistant to small arms. Can attack through walls, hitting objects directly behind them.
  • Health: 375
  • Damage: 30
  • Attack Speed: 1.7 /s
  • Damage Type: Physical
  • Range: 1.5


  • Explosion: 0/10%
  • Physical: 8/10%
File:BehemothBiter-anim.gif Behemoth Biter Extremely durable and nearly immune to small arms, except for the strongest ordnance. Can attack through walls, hitting objects directly behind them.
  • Health: 3000
  • Damage: 90
  • Attack Speed: 1.2 /s
  • Damage Type: Physical
  • Range: 1.5


  • Explosion: 12/10%
  • Physical: 12/10%


Spitters are much like Biters and only appear slightly later on in the game as the evolution factor increases. Their main difference from Biters is their ranged attack. The attack is unavoidable and always hits the intended target. It is also acid-based, and because most entities of the game have a much lower resistance to acid than other damage types (including turrets and armor), Spitters are effectively more potent against the player and his factories. Their behaviour and size classification are the same as with Biters, but their health is universally lower and they are resistant exclusively against explosives, with no physical resistance.

Picture Name Info
File:SmallSpitter.png Small Spitter Weakest of spitters. Easy to kill with any weapon, but attacks at range.
  • Health: 10
  • Damage: 10
  • Attack Speed: 0.46 /s
  • Damage Type: Acid
  • Range: 13
200x200px Medium Spitter Stronger and slower than the smaller version. Can pose a problem for and even kill weaker players.
  • Health: 50
  • Damage: 20
  • Attack Speed: 0.46 /s
  • Damage Type: Acid
  • Range: 14


  • Explosion: 0/10%
File:BigSpitter.png Big Spitter An even bulkier spitter and so can take more damage.
  • Health: 200
  • Damage: 30
  • Attack Speed: 0.46 /s
  • Damage Type: Acid
  • Range: 15


  • Explosion: 0/15%
200x200px Behemoth Spitter The bulkiest of the spitters and so can take even more damage.
  • Health: 1500
  • Damage: 50
  • Attack Speed: 0.46 /s
  • Damage Type: Acid
  • Range: 16


  • Explosion: 0/30%


The Worms are natural allies of Biters and Spitters and will attack the player if they get close enough with an attack similar to Spitters'. They act like static turrets and will not follow attackers. They rely on high damage and great range to keep the player away from the Worms and the nests they protect, but either one of these advantages can be overcome. Unlike other enemies, they are also highly resistant to fire.

Worms come in 3 sizes, their power increasing with size. Unlike Biters and Spitters, Big and Medium Worms are not influenced by the evolution factor, they can spawn at any size right from the beginning. They are not restricted to spawning close to nests, either. The number and size of Worms spawning is instead influenced by the distance from the player's initial spawn point. The further away the player goes from the starting area, the more numerous and stronger the Worms become.

Picture Name Description
File:SmallWorm.png Small Worm A weak worm. It is still capable of killing the player unless it is targeted as priority.
  • Health: 200
  • Damage: 25
  • Attack Speed: 0.91 /s
  • Damage Type: Acid
  • Range: 21
File:MediumWorm.png Medium Worm Medium worms are dangerous to even more advanced players. They should be handled with care.
  • Health: 400
  • Damage: 40
  • Attack Speed: 0.65 /s
  • Damage Type: Acid
  • Range: 25


  • Explosion: 5/15%
  • Physical: 5/0%
  • Fire: 2/50%
File:BigWorm.png Big Worm Big worms are not as much more dangerous as resilient. They are almost immune to common gunfire of any sort.
  • Health: 750
  • Damage: 50
  • Attack Speed: 0.65 /s
  • Damage Type: Acid
  • Range: 26


  • Explosion: 10/30%
  • Physical: 10/0%
  • Fire: 3/70%
Picture Name
Worm.gif Worm's animation


The spawn points of Biters and Spitters. While nests themselves are generally defenseless, the enemies they release overtime effectively serve as a form of guards to distract the player and any nearby turrets, and are often accompanied by Worms. Nests exposed to pollution will use it to evolve the enemies they spawn, which may also result in an attack.

Further away from the starting location, the chances that stronger enemies spawn is higher. This is controlled by the spawn_shift; the higher the value of it, the higher the probability that stronger enemies spawn.

The Nests are highly resistant to fire and otherwise generally more resilient than a Medium Worm.

Picture Name
File:Biternest-anim.gif Biter's Nest
  • Health: 350


  • Explosion: 5/15%
  • Physical: 2/15%
  • Fire: 3/60%
File:Spitternest.gif Spitter's Nest
  • Health: 350


  • Explosion: 5/15%
  • Physical: 2/15%
  • Fire: 3/60%


Every 4-60 minutes, a group of 5-20 biters will leave their base to create a new base. This group will search for a suitable spot that's 3-7 chunks away from existing bases. Once they have found a suitable spot, the group dies and forms a new base. This new base will at first be very small (about one nest and a few worms), but will grow as time passes.


The enemy will only aggressively engage the player's factory if the pollution cloud of the factory reaches a nest.

The biter class enemy will likely be the most common threat to a player's factory. While any attack can catch an undefended factory off guard, most players will be able to handle attacks from small biters with relative ease. Medium biters often pose a much greater threat due to their heavy armor. Big biters are another step in this direction and can come as another nasty shock to any player not familiar with their world's evolution level. Behemoth biters are a big threat to any factory and serve as the Player's prime incentive to avoid excess pollution. However, Biters of any size can be managed by static defense, though some of the larger waves can be overwhelming.

Biters come fairly early to attack a factory that produces large amounts of pollution, as pollution will attract an attack. Once the pollution cloud reaches a nest, the player can expect biters to be showing up shortly. The attack group will be focused on destroying the source of the pollution, but will change targets as soon as one appears of higher priority, typically by level of pollution, though they target the player or static defense first and foremost. Biters also have the ability to find their way around a defense, to a degree. This can be used to partially control the movement of the biters allowing turrets to damage them for a longer time, but requires the "bait" of this trap be left open. Biters aren't always willing to fall for the bait. Some biters will choose the most direct route and will attack the walls of the trap regardless making them less predictable and more dangerous.

Biters are attracted by and enraged by pollution and will attempt to destroy its sources. They prefer to attack the player character, turrets and radars and will stop searching for pollution if they can see and attack any of those. Biters deal physical damage.


Spawn chances of biters from biter spawners by evolution factor. See the table below for exact values.
Spawn chances of spitters from spitter spawners by evolution factor. See the table below for exact values.

The evolution factor is a global variable that determines what kind of biters will be spawned. You can check the variable in the dev console via the following command:


It goes from 0 (not evolved at all) to 1 (maximal evolution). At the moment the evolution factor can only increase. The evolution factor is increased by three kinds of events:

Methods of increasing

  • The passage of time very slightly increases the evolution factor.
  • The global pollution production increases the evolution factor.
  • Destroying enemy spawners significantly increases the evolution factor.

All these values are set in game.map_settings.enemy_evolution. From there they can be changed or modded.

The default settings are:

Source per Variable in enemy_evolution Percent increase
Second time_factor 0.0004%
1000 Pollution Units pollution_factor 0.0015%
Destroyed enemy spawner destroy_factor 0.2%

Pollution production is the total pollution produced by buildings per tick, not the pollution spreading on the map, so it is not reduced by trees or other absorbers. e.g. : 15 burner mining drills produce 150 pollution per second, raising the evolution factor by 0,00000225 per tick.

The percentages are applied on the base of 1 - current_evolution_factor. So for instance destroying enemy spawners in the beginning of the game results in increase of evolution factor by 0.005 (half a percent) while doing this when the evolution factor is 0.5 the increase is only 0.0025 (quarter a percent).

Besides choosing what kind of biter will be spawned the evolution also influences the spawning interval. This interval (spawning_cooldown in the enemy-spawner definition) is interpolated between 360 (0 evolution) and 150 (1 evolution) ticks.

Spawn chances by evolution factor

Biter's Nest
Factor Small Biter Medium Biter Big Biter Behemoth Biter
0% 100%
5% 100%
10% 100%
15% 100%
20% 100%
25% 82% 18%
30% 67% 33%
35% 53% 47%
40% 40% 60%
45% 29% 71%
50% 18% 82%
55% 8% 80% 12%
60% 79% 21%
65% 63% 37%
70% 38% 62%
75% 33% 67%
80% 29% 71%
85% 26% 74%
90% 24% 76%
95% 16% 59% 25%
100% 13% 50% 37%
Spitter's Nest
Factor Small Biter Small Spitter Medium Spitter Big Spitter Behemoth Spitter
0% 100%
5% 100%
10% 100%
15% 100%
20% 100%
25% 100%
30% 42% 58%
35% 100%
40% 100%
45% 83% 17%
50% 75% 25%
55% 54% 36% 10%
60% 35% 47% 19%
65% 17% 56% 27%
70% 65% 35%
75% 56% 44%
80% 45% 55%
85% 35% 65%
90% 24% 76%
95% 16% 59% 25%
100% 13% 50% 37%


  • 0.15.0:
    • Increased the damage, range, and health of worms.
    • Decreased health and resist of Behemoth biters.
  • 0.13.10:
    • Biters and other units won't become aggressive as a result of friendly-fire.
  • 0.13.0:
    • Big and behemoth enemies now spawn 50% slower.
  • 0.12.26:
    • Running biters over with a vehicle will now anger them in peaceful mode.
  • 0.12.0:
    • Updated sounds for enemies.
  • 0.11.17:
    • Items dropped by enemies(*) are now collected automatically and from longer distances.
  • 0.11.6:
    • Range of spitters is now 15, less than turrets.
  • 0.11.0:
    • Spitters added.
    • Drawing of enemies optimised, so adding new colors does not impact VRAM.
    • Blood splashes on death are now procedural.
  • 0.9.0:
    • Turrets no longer search for enemies when none are near.
    • Biters can no longer destroy the shipwreck in the 3rd new hope campaign.
  • 0.8.1:
    • Further improvement to enemy AI.
  • 0.7.2:
    • Biter AI improved.
  • 0.7.1:
    • Peaceful mode added for freeplay.
  • 0.7.0:
    • Enemy creepers were replaced by small, medium and big biters.
    • Enemy turrets were replaced by small, medium and big shooting worms.
    • Enemies move and attack in groups.
    • Enemies wander around their base when they have nothing to do.
    • Enemies call for help when attacked.
    • Enemies can create new bases.
    • Enemies can now destroy all player creations they find.
  • 0.1.0:
    • Introduced, called 'creepers'

See also