To manually set a higher resolution simply edit the TacticalOps.ini which is located in the games “System” folder
Find the following section and set your desired Windowed and Full Screen resolutions
[WinDrv.WindowsClient]
WindowedViewportX=640
WindowedViewportY=480
WindowedColorBits=32
FullscreenViewportX=1920
FullscreenViewportY=1080
FullscreenColorBits=32
