Simon Willison: Claude Opus 5.5 marks a new inflection point for vibe-coded games

Developer Simon Willison says October 2026 is a tipping point for vibe-coding games: Claude Opus 5.5 now handles game design and makes games genuinely fun. He built four browser-based HTML/JavaScript games without touching code, including Emberwick, an RPG with a 15-minute story.

• Willison built four browser games in HTML/JS without editing code
• Tree Appreciator on three.js was generated in a single Claude prompt
• Emberwick RPG has a 15-minute story and a level editor
• Willison says GPT-6 Astra still trails Opus 5.5 on sense of fun