This is a limitation of MIDI, but at 5:30 in the video, he kind of eludes to that ability.

From what I understand, there is a new MIDI implementation called MPE that gets by this limitation using multiple MIDI channels, as CC messages effect all notes per channel. This is the same implementation that the new ROLI Seaboard uses.

The LinnStrument is capable of doing what you ask using "MPE" enabled software or devices. I believe Logic and Bigwig are both MPE capable.


Here's a demo that includes multi-note slides while maintaining accurate pitch.