Now see the reason LM was relatively easy to make (and ran so fast) was:
A. I had color detection and could just draw obstacles such as your trail on the canvas, and
B. It has tile maps which also use the canvas and inherently work with the color detection!
I could try to convert it, but I'd have to add code for the collision with trails (checks EVERY line) and work out how to make the maps without using more than 100 sprites. I just don't know. Maybe?
Aaaaand wait for Gan to tell me to wait for his amazing HTML5 thing because it does all this and SO MUCH MORE! (kidding Gan)
EDIT: If I sat down with that tile engine I just made it might actually work because NO SPRITES. After all, LM was going to use the drawing commands originally anyways,
it all stemmed from my realizing you can draw anything on the TRON game besides the two players' trails. But man I still miss that program.