Claude Opus 5.5 is ridiculous

Summary
In this video by WeeklyHow, the presenter tests Anthropic's Claude Opus 5.5 by having it generate web-based recreations of three popular video games: Call of Duty, Fortnite, and Minecraft. Running the generated Three.js code locally in a browser, the host reviews each game's visuals, mechanics, and shortcomings.

What is shown

• [00:33] Updating the desktop client and selecting Opus 5.5 from a model dropdown list (which also shows Opus 5, Fable 5.1, Sonnet 5, and Haiku 4.5).
• [00:44] Submitting a prompt adapted from Matt Shumer to build a Three.js AAA-style first-person shooter using sub-agents and ultracode in an iterative loop.
• [00:56] Opus of Duty gameplay: Complete start menu, settings options (graphics, field of view, post-processing), wave survival gameplay with ADS iron sights, weapon switching, muzzle flash effects, reload animations, and a side-by-side comparison between Opus 5 and Opus 5.5 at [05:34].
• [05:47] Opusnite (Fortnite clone): Lobby interface, Battle Bus skydiving sequence, glider deployment, terrain exploration with level-of-detail rendering, swimming mechanics, combat, building wooden walls, and fixing aiming/running controls via a chat prompt at [08:30] before achieving a "Victory Royale" at [09:58].
• [10:33] OpusCraft (Minecraft clone): Title screen running in-browser, underwater kelp biomes, breaking ice blocks, third-person perspective toggle, large-scale procedural mountain terrain generation, and block harvesting.

Claims & numbers

• The presenter claims Opus 5.5's Call of Duty recreation is "the best game main menu created by an AI... the best I have ever seen" [01:03].
• The presenter notes that during the Opusnite test, performance remained smooth and "slightly under 60 fps" without lag despite large terrain rendering [08:12].
• The presenter claims previous models could not produce terrain generation of this scale in a single prompt compared to Opus 5.5 [11:19].

Notable quotes

• [01:01] "I believe that this is the best game main menu created by an AI. It's the best I have ever seen."
• [05:31] "The model is working, and it's improving."
• [10:02] "Opus 5.5 did an amazing job with this one. I mean, there were problems that it managed to fix, but overall the whole game is so, so good."

Assessment
This is an independent hands-on review and demonstration exploring coding capabilities for 3D web games. The video displays genuine interactive browser demos, though the gameplay features pre-fabricated 3D assets, placeholder logic, and minor bugs that required targeted follow-up prompting to correct.

Described by gemini-3.8-flash on 2026-09-29 from the video's audio and frames.