While you could use a wall as a projector screen, it’s not an ideal solution for watching movies or gaming. Even if your wall is painted white, it will lack the proper reflective surface resulting in dim images and unnatural colors. Your eye will zero in on any imperfections in the wall, such as a nick or popped drywall nail. And even mildly glossy wall paint will shoot every wave of ambient light at the viewer. When someone opens a door or uses their phone, it can be very disruptive. A portable video screen is a great option. These are relatively inexpensive and the material is designed to display fantastic-looking images, even for video games with high frame rates and billions of colors.