A well-presented lighting engine with some areas to explore, but with a few flaws and some coding quirks the user should be aware about if they look into this code.

1) Low "arcstep" setting leads to chars being missed frequently. This is a counter employed manually by Nytar, presumably to decrease processing costs, which shouldn't really an issue these days. Setting "arcstep" to 1 and commands to 32767 or higher will fix this.
2) Wall detection doesn't always work -- admitted by Nytar himself in the .MZX file. I haven't personally witnessed this, but it's something to keep in mind.
3) This was from the days after trig was added but before local counters were expanded. Thus, Nytar uses "lava_walk" as a local counter.
4) Nytar uses && instead of single quotes in his equations, which works, but looks incredibly strange.

Good job, Nytar!