ENGINE PLAYBOOK

Unity

Find out whether your game uses Mono or IL2CPP before choosing a loader. The backend changes the route.

Read the original playbook

RECOMMENDED ROUTE

Identify backend → compatible community loader → minimal plugin

Identification clues in a local game install:

UnityPlayer.dll<Game>_Data/Assembly-CSharp.dll or GameAssembly.dll

FROM IDEA TO TEST

A practical first workflow

STEP 01

Identify Mono or IL2CPP

Assembly-CSharp.dll in the Managed folder indicates Mono. GameAssembly.dll with global-metadata.dat indicates IL2CPP. Record the game and Unity versions.

STEP 02

Use the community’s route

Look for the game’s supported API or loader first. BepInEx and MelonLoader builds must match the backend and game version. Do not assume a Mono plugin will work on IL2CPP.

STEP 03

Confirm a clean plugin load

Start with a small offline change. Check Player.log and the loader log, then test a scene reload. For BepInEx, inspect BepInEx/LogOutput.log.

What can trip you up

IL2CPP stripping can remove methods and generic types a mod expects.
An engine match is not a compatibility guarantee. Anti-cheat protected online clients are outside this guide.

MAKE IT YOURS

Start with this prompt

Adapt the game and idea to your own copy. This is a planning prompt, not a promise that a mod will work on every version.

Use universal-modder to inspect my owned single-player Unity game. Identify Mono or IL2CPP, the Unity version, any anti-cheat, and the community-supported loader. Explain compatibility before installing anything. Propose one small offline mod and a test using the game and loader logs. Do not bypass anti-cheat or DRM.

Set up your agent

Games in this family

Hollow Knight RimWorld Valheim

Unofficial guide · universal-modder by rehan-remade, MIT · Reviewed October 4, 2026. Source: upstream engine playbook.