BillionNemesis

v4.2.2·Updated 2026-09-21

(Greed fixes) Adds alternate versions of levels with higher difficulty and more interesting enemy arenas

Screenshots 3 screenshots

About this mod Author’s original text

(Use Thorn config to switch between Nemesis and vanilla. Right shift to open by default, under the MISC section)

Billion Nemesis is a mod aims to redo all the arenas in the game by making them more interesting and a lot harder (not meant for a new save). Kind of like Encore levels except it all takes place in the original levels instead of brand new ones

Latest update: v4.2.2 fixes and chagnes

If you find any issues or have other feedback then dm me on discord @somebilly. Also check whether you have all the dependencies for this mod and for Thorn and whether they're updated to the latest versions

Features

  • Currently all campaign levels from 0-1 to 4-4 have new encounters
  • Each layer gets progressively harder than the last
  • Limited use of radiance or enemy spam
  • Occasional level environment changes and new names for the levels
  • Hidden terminals with "dev commentary" in each Nemesis level
  • So-called custom enemies

Credits

  • Mo-Neo - the majority of level names

Information

Generally I tried to use interesting enemy combinations and to play into the environment/level geometry so that you approach things in more unique ways and such. The new encounters aren't limited in enemy types and all enemies can appear from the very start. So I recommend beating all the layers and the Prime Sanctums if you haven't done that yet

Nemesis levels save your progress separately and they have their own rank requirements

Custom enemies

  • Black Hole Launcher (Limbo)

_(Introduced in 1-2)_

(27 health) Fires 1 slow black hole at a time that constantly follows you. Requires you to keep track of its position and to keep moving. If you get hit by the black hole, the launcher will fire the next one 2 seconds later

I know that the black holes don't target you through portals but I don't know how to fix that lol

  • Watchtower (Limbo)

_(Introduced in 1-3)_

(30 health) A tall defense system tower that shoots series of projectiles which predict your movement. If you parry any of the projectiles in the series, the rest will become purple which means they're now unparriable and don't deal damage to enemies. The yellow orb at the top can be parried to deal 12 damage to the Watchtower, either with the feedbacker or the jackhammer. Trying to parry the yellow orb may be dangerous, but it helps to kill the Watchtower a lot quicker

  • Fuchsia (Lust)

_(Introduced in 2-1)_

(16 health) Fires 2 magenta beams back and forth, can't be whiplashed. When you get too close it either: 1) pushes you up if it has wings, 2) pushes you down if it has a crown, 3) damages you if it has neither. Go read the full description under SpawnerArmExtras

  • Enrager (Lust)

_(Introduced in 2-2)_

Idol-like enemy that enrages the target enemy until it's broken. If the target enemy can get enraged on any higher difficulty, then it will still enrage even on lower difficulties

  • Shockwave Shuffler (Lust)

_(Introduced in 2-2)_

(15 health) Creates magenta shockwaves every few seconds (the shockwave speed, size and cooldown can vary)

  • Puppeteer (Lust)

_(Introduced in 2-3)_

Idol-like enemy that creates puppets of the target enemy until it's broken. The cooldown depends on difficulty. In specific encounters, the puppets may not die when the Puppeteer is killed. And the puppet spawning cooldown can also be different on a case-by-case basis

  • Lumen (Gluttony)

_(Introduced in 3-1)_

Idol-like enemy that adds radiance to the target enemy until it's broken

  • Sander (Gluttony)

_(Introduced in 3-1)_

Idol-like enemy that sands the target enemy until it's broken

  • Phaser (Greed)

_(Introduced in 4-1)_

(10 health) A greenish blue Panopticon eye that spawns Geryon's blue beams every few seconds. The beams follow a pattern of 1 beam forward, 2 beams to the side

  • Scorch (Greed)

_(Introduced in 4-1)_

Idol-like enemy that creates a round safe area around the target enemy, limited by a sphere of lava that does 6 damage every 0.2 seconds. The size of the safe area

Install & use Install: BepInEx plugin

  1. The archive from playbuff is the mod itself — usually a BepInEx plugin (a .dll or a plugin folder once unzipped).
  2. Recommended: use a community mod manager (such as r2modman) — pick this game, import the mod, and the manager sets up BepInEx and its dependencies for you.
  3. Manual route: install the BepInEx loader in the game folder, then drop the unzipped .dll or plugin folder into BepInEx/plugins/.
  4. Launch the game — the BepInEx console logs every plugin it loads; seeing this mod in the log means it is installed.

Mods with listed dependencies need those installed too, or they will not load. Options are usually changed in-game or in the plugin's config file.

Dependencies

Install these first, or the mod will not work:

BepInEx-BepInExPackend_4-ThornBillyMod-SpawnerArmExtras

File & checksum

Filename
BillionNemesis-4.2.2.zip
File size
968.4 KiB
SHA-256
1b2b5af595091fd0e706978921211a1b648c54a90cf54c64e8ed1a0652a5cef1
Stored at
2026-10-06 19:23