Absolutely excellent drawing. I run a series on YouTube called "Half-Life Saga" and am shopping along for a new picture for my intro. The previous intro had the picture custom done for it by my friend Michael (AKA Skidd) and was intented for the first Half-Life games. However, upon completing the first games and moving to hl2, I felt that new intro was in order. If I used your picture I would of course give you full credit and link any and all pages you desire in the description of each videos.
Here is an example of what the previous intro was like from an old episode: [link]
The song being used in the new intro will be "Path of Borealis" by Victor Antonov
Anyway great picture and I hope that we can get something mutually beneficial worked out!