So I'm making a basic 2D game in C# XNA. I want it so wherever my character is facing there is a cone of light and only that part of the level is visible while the right of the screen is dark. Please excuse my ignorance, I haven't been working with C# too long.
Well the simplest approach to this would be to simply overlay a dark mask over the right side of the screen. You could do this with a completely opaque black image that covers stuff from view, but I think what would look better is a semi-transparent black image so that you can still see the background and then hide the enemy graphics on that side of the screen.