The kitty graphics protocol lets you send images to display in the terminal. I had a play around with it trying to make a similar GUI. The big gotcha is text rendering. You can either stick to normal grid aligned monospace, or I think you could maybe use a texture atlas, but it's not going to be very efficient at all. I haven't got as far as trying that though.
The videos... while they work are probably uncompressed video which is only going to work well over a very fast network.
I had similar thoughts, because I would disable it probably. But that does not change the fact (and my previous comment) that this is impressive.
Env Vars: What would make sense to me is a global variable the project checks and runs standard text or effects based on the global environmental variable. This way we could just set a single env var in the shell and have it automatically set off (or on for specific apps only) without configurations and commandline options for many programs.