Those are some of the most detailed illustrations I've ever made.
I worked on this with my wife Elisa, who was actually better than me and did some of the best illustrations here (almost all the shoes ones).
It's been great, we used Clip Studio Paint to perfectly simulate the pencil feel and look.
You can't really tell if they're hand-made or digital, except for the fact that's impossible to fit all those details in a hand-made piece.
And that's what Nike was searching for this particular campaign.
Sometimes we still have nightmares about those holes in the fabric...