Same Prompt, Worse Code: User Documents Opus 5.5 Quality Regression Days After Launch
freedomfromfreedom · reddit · 2026-10-02
A developer re-ran the exact same prompt and reference images for a Godot 3D recreation of the 1990 game Lander, comparing Claude Opus 5.5 output from launch day (Sept 23) versus Oct 2. The later output was clearly inferior:
- A new rendering glitch where props snag against world space as the camera moves. Code inspection revealed physics interpolation enabled project-wide, plus Props.cs rebuilding prop lists and resetting counts every frame — a mistake basic Godot docs knowledge would avoid.
- Missing features the launch version had included unprompted: spacecraft break-apart physics, an intro controls menu, camera toggles; bullets also rendered and spawned worse.
The author rules out non-determinism, concludes the model was gimped or silently swapped after 3 days, and demands transparency from Anthropic. Both runs used the Extra High setting, and both repos will be published for inspection.
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