lots of cool stuff going on in this intro!
i didn't get a chance to work it all out yet but here are a couple of things i immediately noticed that might help you start thinking in the right direction. the very first chord he plays is an inverted min7b5 chord with the b5 in the bass. in this case, Em7b5 with a Bb in the bass. he then maintains the Bb pedal tone and follows that up with A7, that same Bb now functioning as the b9 of the A7 chord. so basically, using a common tone to tie the chords together. as he continues, there are a few more instances of the same voicings reappearing in different spots. he is definitely playing off of the changes of the tune, using the chords as a jumping point, but also introducing inversions and voice leading that open up the sound. thinking about how a minor ii-V can have such a different aural quality if the bass notes are the b5 and the b9 rather then the root is really cool! but in general, as you work out more of what he plays, i think you will find that a lot of what is happening is that there are quite a few open voicings (chords that are not in closed /stacked position) and that many of the chords are not in root position.
hope that helps! and let me know if you have any questions. i'm gonna try to get around to figuring out the rest in the next couple days.