People with Intel graphics cards cannot play my game. What is the solution?

Anyone who is not using an Intel graphics card is able to play my Unity game without a problem: http://i.imgur.com/3RtNYIR.png

However, anyone with an Intel graphics card reports that they can only see black models on a blue background: http://i.imgur.com/uLWJDUc.png

Is this a known issue? What is the solution?

Have you tried using a default diffuse shader on at least one affected model to see if it reappears?