Someone on Reddit just built a AAA-quality snow simulation in their browser. Using Claude Opus 5. Millions of snow particles. A character in a robe with cloth physics. Five water-based spells that carve the terrain. A snow surfing system with a wake that throws spray into sunlight. Every footstep displaces snow. Trails form berms at the edges. Trenches slowly refill over time. Spells leave permanent craters. The entire thing runs in one browser tab. WebGPU. No game engine. No 3D modeling software. Just code. He wrote one detailed prompt. Opus 5 planned the architecture, wrote the shaders, built the physics, iterated from screenshots, and documented every decision. 9 hours. ~4 million tokens. You can open it right now and walk around in it. This isn't a demo. This is the kind of thing a small studio would spend months building.