A couple of things I've noticed, his spikes should probably be a bit shorter, also the buckles on his shoes are missing, neither is a big issue as in some official art his spikes were longer (Sonic CD) and the buckles on his shoes were missing in most of the US official art, the shade of blue you chose however is much better than the one I use, though I like to go with Sonic 3 style more than Sonic Generations/Mania style so that's why, anyway looks good I like it :)
A couple of things I've noticed, his spikes should probably be a bit shorter, also the buckles on hi
