✓ Two crowns ✓ Same mass, different density ✓ Vertical slider ✓ Slider works ✓ Slider controls crowns — Slider direction correct ✓ Full slider range — Fall animation ✓ Water displacement ✓ Rising water level ✓ Splash effects — Physics correct ✓ Live mass value ✓ Live volume value ✓ Live density value ✓ Live displaced water ✓ Gilded displaces more — Heureka animation ✓ No external deps ✓ Light bg / dark text ✓ Self-contained HTML
Slider direction is inverted (instructions say "drag up to submerge" but HTML vertical range sliders increase bottom-to-top by default, making top=100=water which contradicts prompt spec), heureka logic is broken (condition `!heurekaDiv.style.display === 'block'` always evaluates to `true` initially but the display never correctly toggles), splash effects are random noise rather than real animations, and crown positioning in the ASCII art doesn't meaningfully reflect different densities at the same submersion depth — both crowns descend identically despite the physical intent.
Slider direction is inverted (instructions say "drag up to submerge" but HTML vertical range sliders increase bottom-to-top by default, making top=100=water which contradicts prompt spec), heureka logic is broken (condition `!heurekaDiv.style.display === 'block'` always evaluates to `true` initially but the display never correctly toggles), splash effects are random noise rather than real animations, and crown positioning in the ASCII art doesn't meaningfully reflect different densities at the same submersion depth — both crowns descend identically despite the physical intent.