Most (if not all) of this video is AI.

I'm not as certain as you seem to be, but I agree it's at least suspicious. The keypress sounds are admitted to be fake in the comments. The way the camera shakes (or doesn't) in response to keypresses seems odd and physically inconsistent over time; same goes for his apparent manual adjustments of its position/angle. Also the way his eyes track when he looks at his notes doesn't seem to be consistent with the screen layout as shown - he looks noticeably far downward when the notes pane on the screen is horizontally level with vim.

How so?