Attachments can be gained by using Weapon Upgrade Kits; up to four can be attached to a single weapon.
Using a Weapon Upgrade Kit gives a choice of 3 or more randomly-selected Attachments for the currently equipped weapon, along with a small boost to its damage (+5%). Attachments with a gold color are rare attachments, which have a low chance to appear as an additional choice in the given selection.
Ammo TP
15% chance to not consume ammo in the magazine. Scales with luck.
Backup
Increases the maximum amount of spare ammo by 40% and grants slightly faster ejection speed. Also increases ammo gain for the weapon by 20%.
Backup Printer
Prints spare ammo (15% of magazine size rounded up) for every 50 heat generated. Production then consumes 10 heat.
Barebone Allocator
Losing shields (or health if no shield) grants ammo regeneration for a duration. Multiple instances can stack.
Digitalizer
Bullets are directed towards the recoil center, increasing overall accuracy and precision. (Bullets have a high chance of choosing a more accurate trajectory)
Dynamic Reflector
Bullets always ricochet from surfaces or gain one additional bounce. Adds 10 armor penetration.
H-P Laser
Adds an aiming laser. Grants movement stabilization and passively reduces weapon deviation.
Hair Trigger
Burst/Full-auto weapons: Turns the weapon semi-automatic and grants a +20% damage boost.
Semi-Auto weapons: Turns the weapon fully automatic.
Semi-Auto weapons: Turns the weapon fully automatic.
Hyper Accelerator
Adds full bullet enemy penetration or increases penetration damage. Increases bullet velocity.
Impact CPU
Increases damage to structures and props by 25%, and reduces enemy health regeneration by 50%.
Last Straw
Last shot in the magazine deals increased damage and inflicts either stun or burn (for each projectile); damage scales with magazine size.
Muzzle Compensator
Increases damage by 15%, but also increases deviation by 3° and recoil by 10%.
Offload Cycler Ultra
Burst fire weapons: Fully removes burst delay.
Semi/Full-Auto weapons: Increases firerate by 40%.
Semi/Full-Auto weapons: Increases firerate by 40%.
Power Link 4x4 Pin
Grants a random bonus for a few seconds on successful active reload.
Reducer
Kills reduce running cooldowns for items by 1 second and decreases weapon deviation by 3°.
Reload Vent
On ejecting, vent heat and return unspent ammunition to reserve. Passively reduces heat generation by 10%.
Short Magazine Spring
Increases magazine capacity by 30% rounded up. Can only be reloaded when empty.
Silver Bullet Alloy
Increases damage against Elite enemies and Bosses by 2% for each 100 maximum health and bullets take down one additional plating.
Tac Grip
Reduces recoil by 20% and deviation by 5° when standing still, but the effect is inactive while moving. Reduces recoil by 5% passively.
Caliber Reduction
Reduces caliber usage or mAH cell.
Reduces deviation and recoil, improves recoil control and increases magazine by 15% rounded up at the cost of 15% damage.
Titanium Rifling
Removes damage falloff over distance or increases distance damage increase. Increases maximum travel distance.
Twin Link
12% chance to fire an extra projectile with slightly increased deviation at no ammo cost.
Vital Data Collector
Every 4 kills grants +25 max health, until +400 max health has been gained. (64 kills.)
Ammo TP MkII
20% chance to not consume ammo in the magazine. Scales with luck.
Cranial Targeting CPU
Deal 100% increased headshot damage but lose 30% damage overall, powering the device costs 10 shields per shot.
Directional Disperser
Converts the weapon for run-and-gun use, strongly increasing deviation, movement stability, and damage. (+20% damage, +20% firerate, -30% recoil and +25-30° deviation.)
Eternium Amalgam
Replaces vital weapon parts with a heavy Eternium metal mixture, strongly increasing weapon performance (+25% damage, +20% firerate, -10% recoil and -3° deviation) but reduces movement speed nearly to a halt when held.
Eraser Cell
Enemies killed whilst holding the weapon spawn red orbs that each grant 2 ammo directly to the non-empty magazine, 50 shield, and 5 heat.
Hotswap
Unlocks all ammo types for all weapons and allows switching of ammo types without ejecting first. Switching ammo types generates 15 heat.
Super Heavy Compound
Bullets are extremely heavy, deal 40% more damage but slightly reduce movement speed and have 30% reduced range with strong damage falloff over distance.
Tri-Bolt-Carrier
Decreases firerate and damage by 20% but fires 2 additional pellets per shot, pulling from the magazine. Increases deviation by 30%, recoil by 10% and minimum heat by 10. Even if the magazine has fewer than 3 bullets, it will still fire 3 shots.
Multiplier
40% chance to gain double ammo from pickups. Switches the weapon to a rapid fire 5-round burst, increases firerate by 25%. Burst weapons gain 3 extra shots per burst.
Lucky Dangle
Kills grant permanent +0.25 luck, stacking up to 400 times. 5% chance to deal 200% damage, can crit.
Wormhole Mags
Increases magazine size by 30%. Headshots return 1 ammo directly to spare ammo.
Notes
- Hot Swap currently unlocks all ammo types for both players in co-op. It is unknown whether or not this is a bug.
- Twin Link increases weapon recoil by 5 when triggered, regardless of the weapon's individual values.
- Twin Link will double pellet count for shotguns and weapons that shoot more than one projectile at once. This also goes for the Twin Link item.
- Tri-Bolt-Carrier, however, will only add 2 projectiles per shot regardless of initial projectile count.
- Wormhole Mags Seems to be bugged as of now. It doesn't refund the ammo to the magazine. Use it only for the Mag Size increment
- Caliber Reduction works by decreasing the overall damage by 15% while every attachment will increase it by 5% thus the reduction would be negated in 2 more upgrades
- Tri-Bolt-Carrier doesn't change the acid ammo pattern, meaning that you will have one projectile be acid in the following pattern:
- The pattern pictured above: [normal | acid | normal | acid | acid] then repeat
Trivia
The digital screen on the Digitalizer upgrade displays the word 'SHRIKE', the screen name of one of the developers.