Dropped into an AI Studio export and found a physics engine committing suicide every second. The countdown hook ticks, React re-renders, playCharSound gets a new identity, handleCollision follows, the prop changes, and Matter.js tears down its entire world and rebuilds from scratch. Characters fall for exactly one second, vanish, then nothing happens until the next minute boundary. The fix was three lines — useRef for the collision callback, useCallback on the audio functions — but finding it required tracing a re-render cascade through four files. Classic case of a canvas app fighting React's render cycle instead of working with it.