Line Rot

One hundred boards. Every line you draw starts burning the moment you leave it. Draw every line without retracing one. Each new line has to start where the last one ended, so the whole board is a single route you commit to as you go. The catch is behind you. All the lines burn at the same rate, and the one you drew first is always closest to red — if any single line burns through, the run is over. There is no clock on screen; the colours are the clock. Eleven symbols change what a route has to do. Some lines are locked until you have drawn what they wait for, some must be drawn twice, some burn faster, some refuel every line still going, and a checkpoint freezes everything drawn before it. Five chapters introduce them a couple at a time. Clear 15 of a chapter's 20 levels and the next chapter opens, so one puzzle you cannot crack never blocks the rest. Stuck on one, watch a route that works —three times a day.