Short answers are best.
When taking questions about your product answer questions shortly. This is a very challenging thing for many people–including myself–to do. If you’re like me, you’ve probably thought out your startup’s issues a thousand different ways. Answer the question with the most concise answer.
(1) In Nick Morgan’s words, “Too many speakers dump way too much information on the audience. Restraint is key.” See: For speakers: three tips to avoid tiring your audience.
(2) For more on demos to VCs and investors, see: (i) How to demo your startup, and (ii) A better way to demo your product.
(3) For more on demos to potential customers, see: (i) Demos can win sales if you do them like this, and (ii) How to demo your product to a potential customer.