I actually already had Unity's 2D lighting (it only exists in Universal Render Pipeline) in the scene, but I wanted to keep the colour palette restricted (the light would sort of have ruined the effect). As for the straight line of sight, it was the easiest line of sight to make (although I spent most of my time programming the orange sprite it to be the right size), and I plan to make different ones in the future. The cone is a good idea!