Many beginners download a Unity project, open it, see dozens of errors, and immediately give up. This commonly happens when a game was created with an old Unity version, outdated plugins, deprecated scripts, or advertising SDKs that no longer work.

The good news is that you no longer need to understand every line of C# before you can begin repairing an old project.

In this tutorial, I will explain how I used Visual Studio Code, the Cline extension, and a DeepSeek Flash model to repair an old Unity game, upgrade it from Unity 2018 to Unity 2021, create a working WebGL build, and submit the finished game to GameMonetize.

The original game was created with Unity 2018, so it was already very old. After opening it in Unity 2021, I encountered many errors caused by outdated scripts, old APIs, incompatible plugins, and WebGL build problems.

Cline inspected the project, edited the scripts, removed incompatible systems, fixed the compilation errors, and continued repairing the project until Unity successfully created the WebGL build.

Afterward, I uploaded the game to GameMonetize, added the promotional image, description, instructions, category, and tags, and submitted it for review.

This tutorial is designed for beginners. You do not need to be an experienced Unity programmer, but you must carefully follow the instructions, test the game, and approve the changes made by the AI agent.

Video tutorial: I also recorded the complete process. Add the YouTube video here after it is published:

What Is Cline?

Cline is an AI coding agent that works inside Visual Studio Code.

Unlike a normal chatbot that only gives you code to copy, Cline can inspect your project files, read scripts, search for errors, edit files, execute terminal commands, and keep working through a multi-step task.

Cline can connect to different AI providers and models. Its official documentation explains that users can select a provider, enter an API key, and choose a supported model from the Cline settings panel. It also supports OpenAI-compatible providers by using the provider’s base URL, API key, and model ID.

For my Unity project, I used a DeepSeek Flash model through Cline.

I initially used the free access available in my setup. When that model or free allowance was no longer available for continuing the task, I added approximately $5 in API credit and continued repairing the project.

The exact free models, prices, and usage limits can change. DeepSeek charges according to the number of tokens processed, meaning that longer conversations, large projects, repeated scans, and large outputs consume more credit.

What I Accomplished with Cline

Using Cline and DeepSeek, I completed the following workflow:

1. Opened an old Unity 2018 project.
2. Upgraded the project to Unity 2021.
3. Allowed Unity to reimport the assets.
4. Opened the project folder in Visual Studio Code.
5. Installed and configured Cline.
6. Asked Cline to inspect the project.
7. Fixed C# compilation errors.
8. Updated scripts that used obsolete Unity APIs.
9. Removed old and incompatible advertising plugins.
10. Repaired GameMonetize integration.
11. Fixed additional errors produced during the WebGL build.
12. Repeated the build and repair process.
13. Created a working WebGL package.
14. Tested the game.
15. Prepared the promotional image.
16. Wrote the game description and instructions.
17. Selected the category and tags.
18. Uploaded the game to GameMonetize.
19. Submitted the game for review.

This does not mean that every task happened automatically without supervision. I still opened Unity, reviewed changes, tested the game, created builds, supplied required information, and confirmed the final submission.

The AI agent performed much of the technical repair work, but I remained responsible for the game.

What You Need Before Starting

Install the following tools before following the tutorial.

1. Visual Studio Code

Visual Studio Code is the editor where Cline will inspect and edit the Unity project.

Install it normally and open it after Unity has created or upgraded the project files.

2. The Cline Extension

Open Visual Studio Code and select the Extensions icon from the left sidebar.

Search for:

Cline

Install the official Cline extension.

After installation, a Cline icon should appear in the Visual Studio Code sidebar.

3. A Supported AI Provider

You need an AI model connected to Cline.

You may use:

• Cline’s own available models.
• DeepSeek.
• OpenRouter.
• Google Gemini.
• Anthropic.
• OpenAI.
• A local model through Ollama or LM Studio.
• Another OpenAI-compatible API provider.

Cline provides a direct DeepSeek configuration option. Its documentation instructs users to open Cline settings, select DeepSeek as the API provider, enter the DeepSeek API key, and select the required model.

4. Unity Hub

Unity Hub allows you to install and manage Unity Editor versions and platform modules.

For this project, I upgraded the game to Unity 2021.

You should also install the WebGL Build Support module for the exact Unity version you plan to use.

5. A Unity Project

You can use:

• Your own Unity project.
• An old Unity game you previously created.
• A legally obtained Unity template.
• One of our free Unity games.
• A project for which you possess the required modification and publishing rights.

Do not download random commercial projects and publish them as your own. You must have permission to use the code, models, textures, music, sound effects, branding, and other assets included in the project.

Important Warning Before Upgrading an Old Unity Project

Never upgrade the only copy of a Unity project.

Before opening it in a newer Unity version, create a complete backup.

For example:

Police Car Parking - Original Unity 2018    
Police Car Parking - Unity 2021 Upgrade

Work only on the second copy.

Unity recommends backing up and preparing a project before upgrading it. Unity also recommends following the upgrade guidance for each intervening Unity release when moving across several major versions.

An upgrade may modify:

• Project settings.
• Package files.
• Materials.
• Shaders.
• Lighting.
• Prefabs.
• Scene data.
• Input settings.
• C# scripts.
• Platform configuration.
• Asset metadata.

Once the project has been upgraded and saved, returning it to the old Unity version may not work correctly.

Step 1: Install Unity 2021 with WebGL Support

Open Unity Hub and install your chosen Unity 2021 editor version.

During installation, select:

WebGL Build Support

You may also install:

Microsoft Visual Studio Community    
Android Build Support    
Windows Build Support

Only install the modules you need.

For a GameMonetize browser game, the essential target is WebGL.

After installation, confirm that the Unity version appears inside Unity Hub.

Step 2: Make a Complete Project Backup

Close Unity before copying the project.

Copy the complete project folder to another location.

A normal Unity project contains folders such as:

Assets    
Packages    
ProjectSettings    
Library    
Logs    
Temp    
UserSettings

For a clean backup, the most important folders are:

Assets    
Packages    
ProjectSettings

However, copying the entire folder is easier for beginners.

You can also create a ZIP archive before modifying anything.

Do not continue until the backup exists.

Step 3: Open the Old Project in Unity 2021

Open Unity Hub and select:

Add project from disk

Choose the copied project folder.

Select your Unity 2021 editor version and open the project.

Unity should warn you that the project was created with an older version.

Confirm that you want to continue.

Unity will begin:

• Reimporting assets.
• Rebuilding the Library folder.
• Updating serialized files.
• Compiling scripts.
• Importing packages.
• Converting some outdated project data.

This can take several minutes or considerably longer for a large project.

Do not close Unity while the initial import is running.

Step 4: Review the First Unity Errors

After the project opens, select:

Window → General → Console

The Console may contain many red compilation errors.

Common upgrade errors include:

• Obsolete Unity APIs.
• Removed methods.
• Missing namespaces.
• Old advertising SDK scripts.
• Old Analytics systems.
• Old Unity Ads integrations.
• Missing packages.
• Broken editor scripts.
• Incorrect assembly definitions.
• Outdated networking code.
• Old GUI functions.
• Missing asset classes.
• Unsupported platform plugins.

Do not randomly delete scripts.

An error in one script can generate many additional errors in other scripts. Fixing the first root error may remove several secondary errors.

Take a screenshot or copy the first errors because you can provide them to Cline.

Step 5: Open the Unity Project in Visual Studio Code

In Unity, you can configure Visual Studio Code as the external script editor.

Open:

Edit → Preferences → External Tools

For External Script Editor, select Visual Studio Code.

You can then double-click a C# script from the Unity Project window.

Alternatively, open Visual Studio Code manually and select:

File → Open Folder

Choose the main Unity project folder, not only the Assets folder.

Correct:

C:\Unity Projects\Police Car Parking

Incorrect:

C:\Unity Projects\Police Car Parking\Assets

Cline needs access to the complete project structure, including Assets, Packages, and ProjectSettings.

Step 6: Install and Open Cline

Inside Visual Studio Code:

1. Open Extensions.
2. Search for Cline.
3. Install it.
4. Select the Cline icon.
5. Open its settings.
6. Select your API provider.
7. Enter your API key.
8. Select your preferred model.

For DeepSeek, the general setup is:

API Provider: DeepSeek    
API Key: Your DeepSeek API key    
Model: Available DeepSeek model

Never share your API key in a video, screenshot, blog post, public repository, or Unity project.

Do not save API keys inside:

Assets    
StreamingAssets    
Resources    
Editor    
ProjectSettings    
README files    
Git repositories

An API key should remain private.

Step 7: Start with Inspection, Not Automatic Editing

Do not begin by saying:

Fix everything.

First ask Cline to inspect the project.

Use a prompt similar to this:

This is an old Unity project originally created in Unity 2018.    
    
I upgraded a backup copy to Unity 2021 for a WebGL build.    
    
First, inspect the project without changing files.    
    
Check:    
    
1. C# compilation errors.    
2. Deprecated Unity APIs.    
3. Missing packages.    
4. Old advertising SDKs.    
5. Broken scene references.    
6. Editor scripts that are incompatible with Unity 2021.    
7. WebGL compatibility problems.    
8. Build configuration problems.    
    
Create a prioritized report.    
    
Explain which errors are root errors and which are secondary errors.    
    
Do not delete assets or rewrite entire systems without my approval.

This allows Cline to understand the project before making changes.

Step 8: Ask Cline to Fix Compilation Errors

After reviewing its report, authorize the first fixes.

Use:

Fix only the confirmed C# compilation errors.    
    
Rules:    
    
- Preserve the existing gameplay.    
- Do not remove working features.    
- Do not change the Unity version.    
- Do not upgrade packages unless required and approved.    
- Do not replace complete scripts unnecessarily.    
- Preserve public variables used by the Unity Inspector.    
- Explain every changed file.    
- Work on the root errors first.

Cline can search through scripts, locate obsolete code, and apply edits directly.

After it finishes:

1. Return to Unity.
2. Allow Unity to recompile.
3. Open the Console.
4. Check whether the red error count decreased.
5. Copy the remaining errors back to Cline.

Repeat this process carefully.

Step 9: Let Unity Recompile After Every Important Change

Visual Studio Code edits the files, but Unity performs the actual compilation.

After Cline modifies scripts:

1. Save all files.
2. Return to Unity.
3. Wait for the loading or compiling indicator to finish.
4. Open the Console.
5. Clear old entries if necessary.
6. Check the new errors.

Do not ask Cline to solve an old error log after the source files have already changed.

Always provide the latest errors.

A useful prompt is:

Unity has recompiled the project.    
    
These are the current remaining errors:    
    
[PASTE THE CURRENT UNITY ERRORS]    
    
Inspect the relevant files and fix only these errors.

Step 10: Repair Deprecated Scripts

Old Unity projects often contain code that was valid in Unity 2018 but produces warnings or errors in Unity 2021.

Typical examples include:

• Deprecated scene-loading methods.
• Old networking APIs.
• Old Unity Ads classes.
• Obsolete Analytics calls.
• Removed GUI systems.
• Old particle APIs.
• Old platform detection.
• Old package namespaces.

Ask Cline to update the scripts while preserving behavior:

Update the obsolete Unity API calls for Unity 2021.    
    
Preserve the original game behavior.    
    
Do not modernize unrelated code.    
    
Do not rename public fields because existing scenes and prefabs may reference them.    
    
After editing, list every obsolete API that was replaced.

This is important because unnecessary renaming can break Inspector references even when the C# code compiles.

Step 11: Remove Incompatible Advertising Plugins Carefully

My old project contained advertising-related systems that were not required for the final GameMonetize WebGL version.

Old plugins can create:

• Compilation errors.
• Duplicate classes.
• Android-only code in a WebGL build.
• Missing namespace errors.
• Obsolete SDK calls.
• Editor import problems.
• Conflicting advertising managers.

I instructed Cline to inspect the existing advertising code and keep only what was required for the GameMonetize WebGL integration.

Example prompt:

Inspect all advertising systems in this Unity project.    
    
The final target is GameMonetize WebGL.    
    
Identify:    
    
- Google Mobile Ads files.    
- Unity Ads files.    
- Old Advertisement API calls.    
- Rewarded video scripts.    
- Android-only advertising code.    
- Duplicate advertising controllers.    
- GameMonetize integration files.    
    
Do not delete anything yet.    
    
First list what can be removed safely and what must remain.

After reviewing the report, approve only the required removals.

Example:

Remove only the advertising plugins confirmed as unused and incompatible.    
    
Keep the GameMonetize WebGL integration.    
    
Before deleting a folder:    
    
- Search for all script references.    
- Check scene and prefab references.    
- Preserve required gameplay callbacks.    
- Report every deleted file and folder.

Always keep a backup because removing an SDK may break buttons, reward systems, or scene events that previously called it.

Step 12: Protect Inspector References

Unity scenes and prefabs can reference:

• Public fields.
• Serialized private fields.
• Component class names.
• Script file names.
• UnityEvent methods.

A script can compile correctly but still be broken if Cline renames something used by a scene or prefab.

Tell Cline:

Preserve:    
    
- MonoBehaviour class names.    
- Script filenames.    
- Public method names used by UnityEvents.    
- Public variables.    
- Fields marked with SerializeField.    
- Existing namespaces unless a change is essential.    
    
Before renaming or removing any of these, explain the risk.

After repairs, inspect important GameObjects for:

Missing (Mono Script)

Also inspect important buttons to confirm their On Click() actions remain connected.

Step 13: Test the Game Inside Unity

Once the project compiles without red errors, press the Play button.

Test:

• Main menu.
• Play button.
• Controls.
• Camera.
• Car or player movement.
• UI.
• Pause.
• Restart.
• Win condition.
• Lose condition.
• Level loading.
• Audio.
• Game over screen.
• Advertising calls.
• Return to menu.

Do not immediately create a WebGL build just because the project compiles.

Compilation success only proves that the C# scripts can compile. It does not prove that the game works.

When you find a gameplay problem, explain it precisely:

The game compiles, but after pressing Play the Start button does nothing.    
    
The button is in the MainMenu scene.    
    
Inspect the button event, target script, scene name, and Build Settings.    
    
Do not change the UI design.

A precise report produces better results than saying, “The game does not work.”

Step 14: Configure the Scenes for the WebGL Build

Open:

File → Build Settings

For Unity 2021, select WebGL as the target platform.

Check that all required scenes are included.

For example:

0 - MainMenu    
1 - Gameplay    
2 - LevelSelection

The first scene in the list is normally the first one loaded by the build.

Confirm that scene-loading scripts use exactly the same names as the scene files.

For example:

SceneManager.LoadScene("Gameplay");

will fail if the scene is named:

GamePlay

or:

GameplayScene

Letter case and exact names matter in many deployment environments.

Step 15: Create the First WebGL Build

Create a separate output folder such as:

Builds/WebGL-Test-01

Do not build directly over your only previous working build.

Select:

Build

Unity will compile the project for WebGL.

This stage can reveal errors that did not appear during normal Editor compilation.

Examples include:

• Unsupported native plugins.
• Platform-specific code.
• Missing JavaScript functions.
• Incorrect WebGL templates.
• Shader compilation problems.
• Memory problems.
• Old advertising code.
• Unsupported threading.
• Build post-processing errors.
• Duplicate plugin files.

WebGL is the browser platform used to run interactive Unity content without requiring the user to install a traditional game executable. WebGL content runs through browser technologies such as JavaScript, WebAssembly, HTML canvas, and GPU-accelerated graphics.

Step 16: Give the WebGL Build Errors to Cline

When the build fails, do not send only a screenshot containing the last line.

Open the Unity Console and build log, then copy the relevant error section.

Use:

The Unity Editor now compiles successfully, but the WebGL build fails.    
    
Here is the current WebGL build error:    
    
[PASTE THE COMPLETE RELEVANT ERROR]    
    
Inspect the project and fix only the cause of this WebGL failure.    
    
Preserve the working Editor gameplay.    
    
After the fix, explain why the error occurred and what file was modified.

Cline may need several rounds to resolve all build errors.

My project also produced additional errors after the initial Unity repair. Cline continued inspecting and fixing those errors until the WebGL build completed successfully.

This is normal. A project can pass one stage and fail at the next.

Step 17: Repeat the Build-and-Fix Cycle

The workflow is:

Cline edits the files    
↓    
Unity recompiles    
↓    
You check the Console    
↓    
You create a WebGL build    
↓    
You copy the latest build error    
↓    
Cline fixes the next issue    
↓    
You build again

Continue until:

• Unity contains no critical compilation errors.
• The WebGL build finishes.
• The output folder contains the expected files.
• The game opens in a browser.
• The controls work.
• No critical browser-console errors appear.

Do not let the AI claim that the game is fixed only because it changed the code. The successful build and gameplay test are the real proof.

Step 18: Test the WebGL Build Locally

A WebGL build should be tested through a local web server.

Opening the HTML file directly may fail because browsers restrict certain file operations.

You can use a local server extension or run a simple server from the build directory.

For example, with Python installed:

python -m http.server 8000

Then open:

http://localhost:8000

Test the game in at least one modern browser.

Check:

• Loading screen.
• First scene.
• Start button.
• Keyboard controls.
• Mouse controls.
• Fullscreen.
• Audio.
• Level transitions.
• Restart.
• Game over.
• Browser focus.
• Game resize.
• Advertising integration.
• JavaScript Console.

Press F12 in the browser and inspect the Console for critical errors.

Step 19: Ask Cline to Perform a Final Project Review

After the build works, use a final review prompt:

Perform a final review of this Unity 2021 WebGL project.    
    
Do not change files yet.    
    
Check:    
    
1. Remaining compilation warnings.    
2. Missing scripts.    
3. Broken scene references.    
4. Unused old advertising code.    
5. WebGL compatibility.    
6. GameMonetize integration.    
7. Build folder structure.    
8. Private API keys or credentials.    
9. Development-only files.    
10. Obvious runtime risks.    
    
Separate the findings into:    
    
- Critical.    
- Recommended.    
- Optional.

Do not automatically apply every optional optimization.

A working project can be damaged by excessive last-minute changes.

Step 20: Prepare the GameMonetize Upload Package

After confirming that the WebGL build works, prepare the package required for submission.

The build folder should contain the Unity WebGL output, commonly including files such as:

index.html    
Build    
TemplateData

The exact filenames depend on your Unity version and WebGL template.

Check that:

• The main HTML file is present.
• The Build folder is present.
• The game files use correct relative paths.
• No Unity source project is included.
• No private API keys are included.
• No unnecessary backup files are included.
• No unrelated executable files are included.
• The ZIP opens correctly.

Create a ZIP containing the required WebGL distribution files.

Do not ZIP the complete Unity project.

Step 21: Prepare a Professional Game Image

Create a clear image that represents the real game.

The promotional image should show:

• The main vehicle or character.
• The actual environment.
• The central gameplay objective.
• Good lighting.
• Clear colors.
• A readable composition.
• No misleading features.

Do not use a promotional image that looks completely different from the game.

For my game, I prepared an image based on the real police-car parking gameplay.

You can improve a real game screenshot, but the final result should still represent what the player will see.

Step 22: Write the Game Description

The description should explain the real gameplay.

Example structure:

Introduction

Explain what type of game it is.

Objective

Explain what the player must complete.

Gameplay

Explain the levels, challenges, obstacles, parking areas, enemies, or scoring system.

Controls

List the actual controls.

Tips

Give useful advice to the player.

Example:

Police Car Parking is a 3D driving and parking game in which you control a police vehicle through challenging city environments. Drive carefully, avoid obstacles, follow the indicated route, and park inside the marked area without damaging the vehicle.    
    
Complete each parking challenge to unlock the next level. Some areas contain narrow roads, barriers, traffic, and difficult turns, so control your speed and approach each parking space carefully.

Do not claim that the game contains features that do not exist.

Step 23: Add the Correct Controls

List every real control.

Example:

W or Up Arrow: Accelerate    
S or Down Arrow: Brake or reverse    
A and D or Left and Right Arrows: Steer    
Space: Handbrake    
Esc: Pause

Test each listed control before publishing it.

Do not copy controls from another game.

Step 24: Select the Correct Category and Tags

Choose a category that accurately matches the game.

For a police parking game, possible categories might include:

Driving    
Parking    
Car    
3D    
Racing    
Police    
Skill    
WebGL

Only use relevant tags.

Do not add unrelated famous game names merely to attract traffic.

Incorrect tags can confuse players and reduce the quality of the submission.

Step 25: Upload the Game to GameMonetize

Sign in to your GameMonetize developer account and open the game-submission section.

Complete the required fields:

• Game title.
• Game ZIP.
• Promotional image.
• Description.
• Instructions.
• Category.
• Tags.
• Supported devices.
• Orientation when applicable.
• Other required information.

After uploading the files, wait for the platform to process them.

Review every field before continuing.

Step 26: Test the Uploaded Version

The local WebGL build may work while the uploaded version fails because of:

• Incorrect ZIP structure.
• Missing files.
• Letter-case differences.
• Compression configuration.
• Server headers.
• Incorrect paths.
• SDK integration.
• Browser security restrictions.

Test the uploaded preview.

Confirm:

• The game loads.
• The loading process finishes.
• The main menu appears.
• The Play button works.
• Controls work.
• Audio works.
• Levels load.
• The game fits the browser frame.
• Fullscreen works when available.
• The GameMonetize integration works.
• The browser Console contains no critical errors.

Do not submit the game for review until the uploaded version works.

Step 27: Submit the Game for Review

After checking the uploaded game and all metadata, use the final submission option.

Before pressing Submit for Review, verify:

Correct game ZIP    
Correct promotional image    
Correct title    
Correct description    
Correct instructions    
Correct category    
Correct tags    
Working controls    
Working WebGL build    
No critical errors    
No private files    
No unlicensed assets

Once everything is correct, submit the game for review.

This completed my full workflow: an old Unity 2018 game was upgraded to Unity 2021, repaired with Cline and DeepSeek, built for WebGL, uploaded to GameMonetize, completed with its image and metadata, and submitted for review.

The Main Cline Prompt I Recommend

Beginners can adapt the following prompt:

This is an old Unity game originally created in Unity 2018.    
    
I opened a backup copy in Unity 2021.    
    
The final target is a GameMonetize WebGL build.    
    
Your task is to help me repair the project safely.    
    
Rules:    
    
1. Inspect before editing.    
2. Preserve all working gameplay.    
3. Do not change the Unity version.    
4. Do not update packages without approval.    
5. Do not delete files without checking references.    
6. Preserve public variables and SerializeField fields.    
7. Preserve MonoBehaviour class names.    
8. Preserve UnityEvent methods.    
9. Do not rewrite complete scripts unnecessarily.    
10. Fix root errors before secondary errors.    
11. Explain every modified file.    
12. Never claim the build works unless Unity creates it successfully.    
13. Never claim gameplay works unless it has been tested.    
14. Ask me for the latest Unity Console error when needed.    
15. Keep only the advertising integration required for GameMonetize WebGL.    
    
First inspect:    
    
- Compilation errors.    
- Deprecated APIs.    
- Old packages.    
- Advertising plugins.    
- Missing references.    
- WebGL incompatibilities.    
- Scene configuration.    
- Build configuration.    
    
Do not modify files until you give me the inspection report.

Prompt for Fixing a Failed WebGL Build

Unity Editor compilation now succeeds, but the WebGL build fails.    
    
Here is the current complete error:    
    
[PASTE ERROR HERE]    
    
Find the root cause.    
    
Requirements:    
    
- Fix only the current build failure.    
- Preserve working gameplay.    
- Preserve Inspector references.    
- Do not remove required GameMonetize scripts.    
- Do not add new packages without approval.    
- Explain exactly what caused the failure.    
- List every file you modify.    
- After editing, tell me how to test the fix in Unity.

Prompt for Removing Old Advertising SDKs

This project contains old advertising systems.    
    
The final target is GameMonetize WebGL.    
    
Inspect the project for:    
    
- Google Mobile Ads.    
- Unity Ads.    
- Advertisement API calls.    
- Rewarded Ads.    
- Android-only advertising code.    
- Duplicate advertising managers.    
- Old SDK folders.    
- GameMonetize integration.    
    
First create a report showing:    
    
1. What must remain.    
2. What is unused.    
3. What is incompatible with WebGL.    
4. What other scripts reference each SDK.    
5. What gameplay could break if it is removed.    
    
Do not delete anything until I approve the report.

Prompt for Preparing the GameMonetize Information

Cline can also help prepare the submission text.

Inspect this Unity game and prepare accurate GameMonetize submission information.    
    
Create:    
    
1. A clear game title.    
2. A detailed description.    
3. Short gameplay instructions.    
4. A complete controls section.    
5. One primary category.    
6. Relevant tags.    
7. A short promotional summary.    
    
Use only confirmed game features.    
    
Do not invent:    
    
- Multiplayer.    
- Online functionality.    
- Character customization.    
- Extra levels.    
- Mobile support.    
- Rewards.    
- Vehicles.    
- Enemies.    
- Game modes.    
    
Ask me when a feature cannot be confirmed from the project.

How Much Did the API Cost?

I started using the free option available through my Cline setup.

After the model stopped working or the free access was no longer enough to continue, I added approximately $5 in API credit. I then continued using the agent to repair the Unity project.

The final cost depends on:

• The selected model.
• The size of the Unity project.
• The number of files Cline reads.
• The length of the conversation.
• The number of repair attempts.
• The size of build logs.
• How often the complete project is scanned.
• The amount of code generated.
• Current provider pricing.

DeepSeek API usage is token-based, so both the information sent to the model and the response generated by it contribute to usage.

Do not assume that every project will cost exactly $5.

A small project may cost less. A large or badly damaged project may cost more.

How to Reduce API Usage

Unity projects can contain thousands of files. Allowing Cline to repeatedly inspect everything will waste tokens and money.

Exclude Generated Unity Folders

Cline normally does not need to analyze:

Library    
Temp    
Logs    
Obj    
Build    
Builds    
MemoryCaptures

The most relevant folders are normally:

Assets    
Packages    
ProjectSettings

Do not send enormous build logs when only the final relevant error section is required.

Fix One Problem at a Time

Bad prompt:

Fix the whole project, improve the graphics, optimize everything, add ads, build WebGL, and upload it.

Better workflow:

1. Inspect errors.    
2. Fix compilation.    
3. Test the game.    
4. Fix scene problems.    
5. Configure WebGL.    
6. Fix build errors.    
7. Test the build.    
8. Check GameMonetize integration.    
9. Prepare submission information.

Start a New Task When Appropriate

A conversation containing a very large history can become expensive because the model may need to process previous context repeatedly.

After finishing one major stage, create a short summary file such as:

PROJECT_STATUS.md

Example:

Unity version: 2021.3    
Original version: Unity 2018    
Target: WebGL    
Compilation: Passed    
Editor gameplay: Passed    
WebGL build: Current error listed below    
Advertising: GameMonetize only    
Removed systems: Old Unity Ads and Google Mobile Ads    
Important scenes: MainMenu and Gameplay

Then start a focused task based on that summary.

What Beginners Must Still Do Manually

Cline can assist with code, but it cannot replace all developer responsibilities.

You must still:

• Make backups.
• Install Unity correctly.
• Open the project.
• Check the Unity Console.
• Approve sensitive changes.
• Test gameplay.
• Test the WebGL build.
• Confirm asset licences.
• Create or approve the game image.
• Check the description.
• Choose accurate categories.
• Verify tags.
• Review the uploaded version.
• Approve the final submission.

Do not allow an AI agent to approve legal declarations on your behalf.

Do not provide unrestricted access to:

• Email accounts.
• Payment accounts.
• API dashboards.
• Developer accounts.
• Password managers.
• Private keys.
• Banking information.

Common Problems and Solutions

Cline Cannot See the Unity Error

Copy the error as text from the Unity Console.

Include:

• The first error.
• The file path.
• The line number.
• Related errors.
• The relevant build-log section.

Do not provide only:

Build failed

Unity Shows Errors After Cline Says It Is Fixed

Cline edits files, but Unity must recompile them.

Return to Unity and wait for compilation.

Then provide the latest errors.

Cline Deleted Something Important

Restore it from your backup or Git history.

This is why a backup is mandatory.

The Editor Works but WebGL Fails

Editor compatibility and WebGL compatibility are not identical.

Copy the WebGL-specific error and ask Cline to fix only that platform problem.

The Build Works Locally but Not After Upload

Check:

• ZIP structure.
• Main HTML file.
• Build paths.
• Letter case.
• Compression.
• Missing files.
• Browser Console.
• GameMonetize integration.

The API Credit Is Consumed Too Quickly

Reduce unnecessary project scans, exclude generated folders, shorten logs, divide the work into smaller tasks, and avoid repeatedly asking the model to review the entire project.

Visual Studio Code Shows Unsupported Unity Project Warnings

Unity may generate traditional .csproj files that some modern .NET tooling does not load as standard SDK-style projects.

This warning does not automatically mean the Unity game cannot compile.

Unity remains the primary authority for compiling the project. Check the Unity Console and WebGL build result rather than relying only on the Visual Studio Code project-system warning.

Can Someone Who Does Not Know Unity Follow This Tutorial?

Yes, but the person must follow the process carefully.

A beginner can:

1. Download a permitted Unity project.
2. Make a backup.
3. Open it in the correct Unity version.
4. Install Visual Studio Code.
5. Install Cline.
6. Connect an available AI model.
7. Ask Cline to inspect the project.
8. Approve controlled fixes.
9. Copy Unity errors to Cline.
10. Repeat until the project compiles.
11. Test the gameplay.
12. Create a WebGL build.
13. Fix build errors.
14. Test the browser build.
15. Prepare the GameMonetize submission.
16. Upload and test the game.
17. Submit it for review.

However, using AI does not guarantee that a game is good enough to publish.

The game should still have:

• Working controls.
• Clear instructions.
• Complete levels.
• Proper sound.
• Reasonable graphics.
• Fast loading.
• A functional menu.
• A restart system.
• No serious bugs.
• Accurate promotional content.
• Properly licensed assets.

The purpose of this workflow is not to submit more unfinished AI-generated games. It is to help beginners improve and repair games that would otherwise remain unusable.

Follow the Complete Video Tutorial

The written tutorial explains the complete workflow, but the accompanying video will show the real process on screen.

In the video, users will be able to see:

• Visual Studio Code.
• The Cline extension.
• The selected DeepSeek Flash model.
• The Unity project files.
• The repaired scripts.
• The old advertising systems.
• Unity compilation.
• WebGL build errors.
• Cline fixing the errors.
• The successful WebGL build.
• GameMonetize upload.
• Promotional image upload.
• Description.
• Category.
• Tags.
• Final submission for review.

Add the video link here:

Watch the Full Tutorial on YouTube

[INSERT YOUR YOUTUBE VIDEO LINK HERE]

Follow the video step by step and pause it whenever you need to copy a prompt or complete a Unity action.

Final Result

I began with an old game created in Unity 2018.

After upgrading it to Unity 2021, the project contained numerous errors and outdated systems. Using Visual Studio Code, Cline, and a DeepSeek Flash model, I was able to inspect the project, update old scripts, remove incompatible advertising code, fix compilation errors, repair WebGL-specific problems, and create a successful browser build.

I then prepared the game image, description, instructions, category, and tags, uploaded everything to GameMonetize, tested the uploaded version, and submitted the game for review.

The most important lesson is that beginners no longer need to abandon every old Unity project simply because they encounter code errors.

With a backup, clear instructions, controlled AI access, careful testing, and a small API budget when required, Cline can act as a practical Unity repair assistant.

It does not replace Unity knowledge completely, and it should not be trusted without supervision. However, it can make complicated project upgrades and WebGL error fixing much more accessible to developers who are still learning.