This is a highly massaged version of my previous Marcus portrait. I had been waiting for a reason to correct a plethora of issues with my original piece, and this contest has forced me to step it up.
The base image for Marcus was extracted from the first Gears of War cover art and then used to stencil out the rough lineart, which I modified quite a bit to get my own pose down. After the lineart was complete, I then textured and painted the image using a Wacom tablet and Photoshop.
The download file is 2560x1440 at 240dpi, so it does meet or exceed the minimum size requirements.