knuckles is the man. well try turning the opaqicity down on your brush tool (can you do that in oekaki? im assuming so.. never really used that one..) and use more than one shade of the color to give him a more 3d look.. looks like you only used 1 layer, so try using mutiple ones if you didnt already..

good job though

W00t! It's Knuckles! He is such the best character on Sonic Adventure 2 battle! Great Job!