This is a trimmed screenshot of my game that is zoomed in. If you look at where to light hits the wall, it looks uneven. It seems that the lightrays randomly hits the wall, or one pixel into the wall, making it look like this.
I managed to fix this by modifying the script a little bit:
The change I made was that when ray collides with the wall, it goes back 1 pixel, and collision checks that last bit with extra precision. This will cause a few more collision checks (up to four), but it will make the light hit the wall smoothly.
I'm not exactly sure why that happens in your game. Are your solids rectangular or not? It's pixel-perfect no matter what I throw this example in, from curves to flats it makes no difference to me. Could it possibly be the way you're drawing the light?