Excellent first vector. If you hadn't said it, I wouldn't have thought it was. The line art is very smooth and bold, which I like. Nice job with the gradients on their shirts too, it would have been nice to see gradients everywhere though. But awesome job!
This is kind of random, but you have the same background color for your first vector that I used for mine. XD Except yours came out 100 times better. :)