Opus 4.5 vs GPT-5.1 Codex MAX – Optimal Workflow REVEALED! (Game Build Test)

Claude Opus 4.5 vs GPT-5.1 Codex MAX — this test uncovered a surprising workflow for AI-powered game development inside Cursor.

Both models get the exact same prompt and empty environment as they attempt to build a Tower Builder game completely from scratch.

We compare build time, code structure, gameplay mechanics, UI quality, and debugging ability, and the difference between them is bigger than expected.

By the end of the video, you’ll see a clear pattern emerge… and it might change how you use these models together.

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⏰ TIMESTAMPS

00:00 Introduction
00:38 Test: Create a tower builder game from scratch
01:00 Reviewing the prompt for game build test
01:43 Opus 4.5 self-testing with browser sub-agent
02:47 Reviewing build time and code structure
03:29 Testing Opus Tower Builder
04:29 Testing Codex Tower Builder
06:26 Asking Opus to fix game mechanic
07:42 Takeaways — insights & workflow considerations

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🔥 WHAT YOU’LL SEE

• Side-by-side game build comparison
• Differences in code structure & architecture
• How each model handles game logic & physics
• UI/visual quality comparison
• Opus’s autonomous browser-agent testing in action
• Real-time debugging and patch attempts
• A surprising workflow pattern that emerges from the test

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🧪 MODELS TESTED

• Claude Opus 4.5
• GPT-5.1 Codex MAX

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📚 RELATED VIDEOS

• Opus 4.5 vs Codex vs Gemini – Productivity App Build Test
https://youtu.be/e-d-YGUnKfg?si=3uHVY68Aw28_Ha80
• GPT-5.1 Codex MAX – Deep Dive & Game/UI Tests
https://youtu.be/2t9fFyP5Po8?si=HO8JkZlu2NpbZc83
• Gemini 3 Pro vs Codex – Snake Game Challenge
https://youtu.be/qVDhEeovAdE?si=0tqa6Qp7Z1oXcwj8
• Antigravity IDE Setup (Google’s New AI IDE)
https://youtu.be/1wP97Rd62cg?si=tzLFb0xG-ad9VXwd
GPT-5.1 Codex is AMAZING (Comparing output to GPT-5): https://youtu.be/4hQfWfRdRks?si=_YhoyGmy123Nf8B-

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