Hey gansorx,
I can see the issue you are having, but I need a bit more information in order to assist you. When you press play, are you playing in a separate window, stand-alone game, or within the editor itself? If playing in a separate window or stand-alone game the resolution of your window can affect the overall visual quality of your scene. Try pressing Play in Editor (PIE) to see if your scene quality changes.
Thank you,