Maybe a short, abstract svg animation of how a certain feature would look like and behave? Probably a little more work to implement (well) and keep up to date but I've liked that sort of thing on the few sites I've seen it on in the past. Sadly can't think of any right now though.

I also remember algolia having some sort of movie search demo as their top banner a few years ago. Including their completion and such. Always struck me as a good way to introduce their service in particular.

I feel like this much content needs it's own section. Having the onhover on my cursor that resizes and moves around so much as a move the mouse or page up/down is pretty horrible UX. I'd do something like how MS Excel has Task Panes on the right of the window. Then each thing can have an image/video and a paragraph explaining and showing what it is. The main issue here though is he's trying to explain/list all these tiny little features instead of just simplifying the page which is probably causing analysis paralysis and hurting conversions, so adding more information is probably just salt in the wound. He really just needs to get people to sign up and see the features and they'll be self explanatory, up sale from there.