Unity Apk size is too big for building the same scene

Unity Engine
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1

I’m Developing a game that should have 15-60 levels when all the environments of the levels are the same. I created a scene (level1) and tried to build it the total apk is around 38Mb which is fine. But When I duplicated this scene to create the other levels and build my game the file size jumps to 148Mb which is problematic for me. Also, I’m using URP. and I have all the repeated components as prefabs

Things I tried:

  • I Optimized meshes, textures, and audio files.
  • I tried toggling static batching, SRP batching, GPU Instancing.

Here’s some of the editor log of the second build:

Build Report
Uncompressed usage by category (Percentages based on user generated assets only):
Textures               6.2 mb    1.8%
Meshes                 3.1 mb    0.9%
Animations             781.3 kb  0.2%
Sounds                 0.0 kb    0.0%
Shaders                1.8 mb    0.5%
Other Assets           652.6 kb  0.2%
Levels                 323.1 mb  91.6%
Scripts                3.6 mb    1.0%
Included DLLs          13.4 mb   3.8%
File headers           105.1 kb  0.0%
Total User Assets      352.8 mb  100.0%
Complete build size    678.6 mb
Used Assets and files from the Resources folder, sorted by uncompressed size:
2.2 mb  0.3% Assets/Polygon/PolygonSamurai/Models/Characters.fbx
1.2 mb  0.2% Packages/com.unity.render-pipelines.universal/Shaders/PostProcessing/UberPost.shader
1.0 mb  0.2% Assets/TextMesh Pro/Resources/Fonts & Materials/LiberationSans SDF.asset

I’m sure I’m doing something wrong I don’t know where is the main problem. Any help is soo appreciated.

2

So what worked for me is that I placed everything in one scene I created a prefab of every environment, and created a game object for each level initially turned off then I created a script that loads a certain level and turns on/off the corresponding level objects and environment.

With this, my game composed of 15 levels jumped from 440Mb to only 45Mb.

Note: I used GPU instancing for the materials and turned off static batching for all elements especially trees.