Nice,
Wow, the lighting effects are really cool, it's pretty stylized too. The only major thing I though was a little off is that deeper in the cave should be darker as it probably has no light source and the contrast between the light and dark would probably makes it seem like it's pitch black just by looking at it. Another thing is that the picture looks a little pixelated in some places (visible in the larger scale view) and it would help if you fixed that(primarily because I think that the best way to view the immense amount of detail in this picture is through seeing it in its original size.