Out of experience I tell you Demos are not about showing all of your product the way it is, or at the speed it runs.
It would be good if you could entertain your prospect clients along the showing, which is exactly that: "showing".
You should script what you will be showing of, then make specific pages for such purpose, speeding them up. How? for example your form loads a lot of complicated data because it's good and has many variables, but that maybe cost heavy resources comsuption somewhere, call it database, data transfer, asynchronous queries, whatever. In that case, make "demo shortcuts" (next thing to hardcoding ) and script your show to work with that set of flashy data.
Also, is important how you speak, and if you could make some joke (common people joker rather than IT joke) while working the controls and the crowd, and if you also, present real cases analogies with that (real cases pertinent to your audience) and offer some insight on future features you are working on (even if you aren't) . That gives prospect client sense of continuity, and that they are part of a developing the future experience.
The app itself? Do you like to watch a twenty minutes slideshows on the board's meeting? Do you like sales speeches? Neither does your clients
Go get them tiger.