is that a micron inking pen I see in there?? haha. amazing detail - AMAZING. Style is so smooth and I like how everything has a sort of "flow" to it with the curvyness.
I also concur with one of the commentors above that light from a screen usually isn't that bright, and does have a more of a blue-ish hue. And I can also understand that it would conflict with your background. But I think if you dim down or maybe tone the light from the computer a little blue, it really won't conflict with the background. Just a suggestion.
Otherwise this is fantastic progress, and I'm sure once it's done it'll be even more amazing. Keep it up!
Suggestion: Increase the light value away from the character a bit, I understand that if he looked blue, he would just mush into the foreground, but that isn't always a bad thing. Increase the light above the cactus and Styrofoam cups, and add a blue hugh from the computer screen, You never know, it might work out.
My only trouble with this is that I think lights from screens usually is bluer, at least bluer than spots or other lamps (captured on tape that is), however, it may not work as well with the background, so I understand you.
I can't wait to see the final thing, looks awesome.