Ah, the conundrum of being "polite" or brutally honest...

Personally, I'd take brutally honest anyday, because honest critique is invaluable if you want to improve and grow. Whether such critique was warranted in the first place is the issue. Hence my earlier question.... what was the purpose of putting up the video?

Otherwise, what's the point? We can all pat each other on the back and say, yeah, nice demo... That'd be the "polite" thing to do, but it doesn't give the OP any feedback other than to, IMO inappropriately, validate the performance.