I started out with a handdrawn one-point-perspective drawing that I scanned in.

 

I then made a grayscale by first blocking in the different faces and afterwards put some depth in it with a lightsource. I made two of these, one with the lightsource being the camera and this with the lightsource being the perspective point.

I then put in the colours and I made a blured version to put behind it to give a less hard feel, but still keeping the spikes. I had a problem with my monitor being much different from standard regarding colours so I had to test and tweak to get the colours to show on other monitors.

The necessary lensflare version.