Chen-ChensGradiusMod icon


This mod aims to implement features from classic shoot-em-up games. It contains a fully functional Drone API, fully documented. It also improves behavior and mod compatibility of drones.

Last updated 3 months ago
Total downloads 72774
Total rating 12 
Categories Mods Libraries Tweaks Items
Dependency string Chen-ChensGradiusMod-3.4.3
Dependants 20 other mods depend on this mod

This mod requires the following mods to function

bbepis-BepInExPack-5.4.9 icon

Unified BepInEx all-in-one modding pack - plugin framework, detour library

Preferred version: 5.4.9
tristanmcpherson-R2API-3.0.44 icon

A modding API for Risk of Rain 2

Preferred version: 3.0.44
ThinkInvis-TILER2-5.0.1 icon

ThinkInvisible's Library of Extras for RoR2.

Preferred version: 5.0.1
Chen-ChensHelpers-1.0.15 icon

This mod includes helpers that may aid other mod creators. Fully documented, so feel free to check it out.

Preferred version: 1.0.15


Version Build License: GPL v3 Support Chen

GitHub issues GitHub pull requests Maintenance Status

RoR2: Chen's Gradius Mod


This mod aims to implement features from the Gradius series as well as from other classic shoot-em-up games. The mod also changes some vanilla aspects of the game regarding drones.

It contains a fully functional Drone API. The documentation can be found in the wiki.


Use Thunderstore Mod Manager to install this mod.

If one does not want to use a mod manager, then get the DLL from Thunderstore.


Gradius' Option Gradius' Option

  • A new Red Item added to Risk of Rain 2. Upon receiving this item, all owned drones of the receiver will gain an Option/Multiple for each stack.
  • Gradius is known for its feature of Options/Multiples where in these weapons are invulnerable to all damage, and are able to copy the full arsenal of the main ship.
  • For this mod, the Options/Multiples will only copy the main attacks of the drone.
  • All vanilla minions (both mechanical and organic) are supported.
  • All drones from this mod are also supported.
  • Options/Multiples are able to duplicate all attacks of Aurelionite. The Rock Turret will attack faster instead of being copied.
  • Options/Multiples will only duplicate the ranged attack of Beetle Guards. Their melee attacks will have multiplied damage, however.
  • Equipment Drones will use the attached equipment depending on the number of Options/Multiples it has. This is configurable.
  • Documentation is available for other mod creators. Check the wiki.

Gradius' Option Seed Gradius' Option Seed

  • A new Green Item added to Risk of Rain 2. Upon acquiring this item, 2 Option Seeds will spawn for the player. They will duplicate the survivor's attacks for a % of damage dealt.
  • The Option Seed is a fragment of the completed version of it. While it is in its younger stage, it is more organic than mechanical.
  • Only offensive skills of vanilla survivors can be duplicated.
  • The API makes it possible to implement customized skill behavior, even with non-offensive ones.
  • Documentation is available for other mod creators with modded survivors. Check the wiki.

Beam Drone Beam Drone

  • A drone powered by this mod's API. Check the wiki on how to add your own custom drone.
  • This drone shoots a continuous beam on its target.
  • The drone is accurate, however, it is weak at keeping its lock on consistently.
  • The drone will appear in Stage 3 and onwards.
  • The drone will spawn more in Sky Meadow.
  • Options also copy this drone's attacks.

Laser Drone Laser Drone

  • A drone powered by this mod's API. Check the wiki.
  • The drone charges for a short amount of time, and then unleashes a strong laser attack, dealing huge amount of damage in an AoE.
  • The drone will appear in Stage 3 and onwards.
  • The drone will spawn more in Sky Meadow.
  • Options also copy this drone's attacks.

Psy Drone Red Psy Drone Green Psy Drones

  • A drone powered by this mod's API. Check the wiki.
  • Each drone unleashes strong and unique laser attacks.
  • The drones can be bought as one.
  • If one of them is destroyed, the other will also be decommissioned.
  • Upon being destroyed, the first one to make contact with the map will spawn the interactable again if it is configured to be repurchaseable.
  • The drones may appear as soon as in Stage 1, but it is expensive.
  • Options also copy each drone's attacks, although not completely.

Artifact of Machines Artifact of Machines

  • An artifact added to Risk of Rain 2. Survivors will have a TC-280 Prototype drone when they spawn. Enemies, however, will also get drones.
  • The Bacterian essence has drifted towards the embrace of the Planet. The Bulwark deemed it dangerous, and thus keeping it sealed in an artifact.
  • No more drones can be repurchased when this artifact is active.
  • When the owner dies, the drones will be decommissioned as well.
  • Enemy drones will also have Gradius' Option if the Artifact of Evolution gives the item to the enemy.
  • Configure Gradius' Option so that it is not blacklisted.

Other Features

  • Emergency Drone's Null Exception Reference fix. Configurable to be turned off.
  • Allows all drones to be repurchaseable. Configurable each.
  • Allows an Equipment Drone to have a chance to drop its equipment upon being destroyed. Configurable.
  • Makes the Flame Drones spawn more in Abyssal Depths. Config options also offer to allow Flame Drones to spawn more in Scorched Acres.
  • Changes vanilla drone behaviors to be smarter, eliminating the problem of them attacking their own owners as well as widens mod compatibility.
  • Set category of Gunner Turrets as Drones instead of Miscellaneous so that the Director will not spawn too many Gunner Turrets. Configurable.

Contact & Support

More Information

Kirbsuke#0352 made the 3D model for the Option/Multiple, and later used for the icon.

manaboi#4887 helped me edit the icon to make it look like one with vanilla items. Also made Artifact of Machines icon.

  • Contact: Through Discord.

KomradeSpectre#8468 made the 3D model for the Beam Drone and Laser Drone, which was also used for their icons.

  • Contact: Through Discord.



  • Properly apply HGStandrad Shaders to the mod assets. They should look better now.
  • Properly add smoke broken effect for each Psy Drone.
  • Optimize resource loading.


  • Fix a bug in the yellow laser attack of the Green Psy Drone where an exception may occur.
  • Fix a bug where as the Green Psy Drone is duplicated upon going to the next stage.


  • Implement Arms Race support for Psy Drones.
  • Fix a bug regarding double damage in multiplayer.


  • Implement Psy Drones, a powerful weapon from a different timeline.
  • Allow the other custom drones from this mod to benefit from attack speed bonuses.
  • Fix a very bad bug where the Health Components of custom drones aren't properly assigned.
  • Actually add a config option for custom drones to be repurchaseable.
  • Integrate breaking changes from Chen's Helpers.


  • Update the mod so that it works after the breaking changes of Chen's Helpers.
  • Implement a new API for a shortcut way to setup custom broken drone models.

For the full changelog, check this wiki page.

Available versions

Please note that the install buttons only work if you have compatible client software installed, such as the Thunderstore Mod Manager. Otherwise use the zip download links instead.

Upload date Version number Downloads Download link  
2021-7-14 3.4.3 11937 Version 3.4.3 Install
2021-7-10 3.4.2 2372 Version 3.4.2 Install
2021-7-8 3.4.1 1124 Version 3.4.1 Install
2021-7-8 3.4.0 57 Version 3.4.0 Install
2021-6-30 3.3.11 2909 Version 3.3.11 Install
2021-6-26 3.3.10 1778 Version 3.3.10 Install
2021-6-25 3.3.9 469 Version 3.3.9 Install
2021-6-21 3.3.8 1979 Version 3.3.8 Install
2021-6-20 3.3.7 582 Version 3.3.7 Install
2021-6-20 3.3.6 162 Version 3.3.6 Install
2021-6-16 3.3.5 1507 Version 3.3.5 Install
2021-6-14 3.3.4 1087 Version 3.3.4 Install
2021-6-13 3.3.3 939 Version 3.3.3 Install
2021-6-12 3.3.2 665 Version 3.3.2 Install
2021-6-11 3.3.1 663 Version 3.3.1 Install
2021-6-11 3.3.0 56 Version 3.3.0 Install
2021-6-4 3.2.0 2173 Version 3.2.0 Install
2021-5-21 3.1.2 3250 Version 3.1.2 Install
2021-5-19 3.1.1 1215 Version 3.1.1 Install
2021-5-17 3.1.0 1949 Version 3.1.0 Install
2021-5-4 3.0.2 2347 Version 3.0.2 Install
2021-5-4 3.0.1 58 Version 3.0.1 Install
2021-5-4 3.0.0 336 Version 3.0.0 Install
2020-12-14 2.2.11 9886 Version 2.2.11 Install
2020-12-13 2.2.10 525 Version 2.2.10 Install
2020-12-12 2.2.9 254 Version 2.2.9 Install
2020-12-12 2.2.8 340 Version 2.2.8 Install
2020-12-11 2.2.7 431 Version 2.2.7 Install
2020-12-8 2.2.6 648 Version 2.2.6 Install
2020-12-5 2.2.5 962 Version 2.2.5 Install
2020-12-1 2.2.4 849 Version 2.2.4 Install
2020-11-30 2.2.3 453 Version 2.2.3 Install
2020-11-29 2.2.2 362 Version 2.2.2 Install
2020-11-29 2.2.1 300 Version 2.2.1 Install
2020-11-28 2.2.0 381 Version 2.2.0 Install
2020-11-20 2.1.4 1202 Version 2.1.4 Install
2020-11-19 2.1.3 395 Version 2.1.3 Install
2020-11-16 2.1.2 786 Version 2.1.2 Install
2020-11-15 2.1.1 4944 Version 2.1.1 Install
2020-11-13 2.1.0 553 Version 2.1.0 Install
2020-11-12 2.0.0 345 Version 2.0.0 Install
2020-10-27 1.7.0 2583 Version 1.7.0 Install
2020-10-24 1.6.4 1569 Version 1.6.4 Install
2020-10-22 1.6.3 581 Version 1.6.3 Install
2020-10-21 1.6.2 411 Version 1.6.2 Install
2020-10-20 1.6.1 396 Version 1.6.1 Install
2020-10-19 1.6.0 208 Version 1.6.0 Install
2020-10-17 1.5.1 666 Version 1.5.1 Install
2020-10-16 1.5.0 577 Version 1.5.0 Install
2020-10-15 1.4.1 336 Version 1.4.1 Install
2020-10-15 1.4.0 78 Version 1.4.0 Install
2020-10-12 1.3.4 861 Version 1.3.4 Install
2020-10-11 1.3.3 595 Version 1.3.3 Install
2020-10-10 1.3.2 108 Version 1.3.2 Install
2020-10-9 1.3.1 575 Version 1.3.1 Install