Before you play, read the instructions: Move with WASD and point with your mouse cursor Hover your mouse over the top left corner to see the variables. Rays are how many rays it shoots out. Vision is how spread out the rays are, I recommend 180 or 360. Shade toggles, uh, a thing that you'll see when you activate it. It's hard to describe. Also, quick warning, it always sets the rays to 300 so the effect works, be careful of that. (its REALLY laggy) I recommend using Turbowarp if you want it to be a bit less laggy, and only use rays from 1 - 80. Go to 299 if you want to suffer. :] Ray amounts that are under 20 is the sweet spot, with really smooth framerates.
Feel free to remix and customize the code or room.