tl;dr: Using Claude Fable 5.2 with Claude Code, the author one-shotted a complete 12-level, 4-player beat 'em up game for his nephew based on hand-drawn character designs, generating ~175 images (via ChatGPT Images 2.5) and ~140 audio clips (via ElevenLabs) overnight. The agent rewrote most of the existing code, built a bot to playtest all levels in a headless browser, and produced cutscenes, music, and an announcer unprompted. Total cost: ~340M tokens across 600 requests over two days, eventually expanding to 18 unlockable characters based on family members.