This is a simple enhancement for the default Win32 icon for Doom 3. The default icon maxes out at 48x48, so I took the texture pentastic1.dds from the demo and created an icon with a maximum resolution of 512x512.
Pentastic1.dds is 512x512, but the DXT1 compression results in severe macroblocking. Therefore, it has been cleaned up with BlueAmulet's 1xBC1Smooth2 ESRGAN model. Additionally, all the original icon sizes are taken from the original icon due to the texture becoming less clear at resolutions below 64x64.
Doom3.ico is the icon. pentastic1.dds is the original texture, and Pentastic.png is the version cropped to a circle and cleaned up.