Spirit Bomb

First off, I definitely love the musculature and desperate expressiveness of Goku's face. You can really tell he's going for broke in this situation.

For the critique portion, I like that you're bringing in some of the blue of the Spirit Bomb and have chosen cooler tones in accordance, but as far as the coloring goes, I think you'd really find success in your colors if you rendered according to volume rather than contour. I can see some of that going on with the use of lines going in different direction within the shadows, but it could stand to be taken further with another level of highlight and/or shadow on the figure. Right now, the colors really flattens out what had initially started as a somewhat hearty drawing. Think about the planes of the body and render according to those planes, rather than containing highlights to the edges.

On the Spirit Bomb, I think I can see what you were going for, but it feels more like Goku is in a swirling vortex instead of having a ball of energy hovering over his head. I think perhaps having a clear divide where the ball begins would have been better, as well as toning down the lines of color toward the top.

Overall, I think this is a strong piece that captures the very essence of DBZ, and while it's already impressive, could definitely be even more impressive with some refining.