Here are a few examples of recent pieces of a Concept Art nature, (i.e. characters, environments etc., done in accordance with specific briefs). Crits welcome, commissions and job-offers yet more so. (Will work for money).
The first one has some amazing rendering features, cool, it would be good to see the sword finished, though.
The rest needs more work on the rendering and colors, it could be more vivid.
I like the three concepts though
nice job, especially on the first one!
The last one looks a little... lacking, as if it might not be finished yet. I think adconcept is right that you could bring out the colors a lot more. Also, there's almost no way to tell that there's movement in this last piece, except for the face that it's cars and they should be moving. I think a more dramatic angle could help this as well as some blurring techniques to suggest speed. Also try adding some flying debris, smoke, sparks, etc. Here's a couple references I think would help a lot:
Anyway the first pic is pretty cool, could use some work on the background the character seems a little stiff. Rendering on the character looks good though. The next few pieces have really muddy colors though, so try to work on getting things to look more vibrant or more purposely dirty. That troll guy's skin looks really pale so he look sickly, and he needs to look more grounded. Check out Jason Chan's work to get help on that. Parcel posted some good images to use as reference for the cars. .
Nice images, need a bit more finishing up here and there