You should improve very fast, Slides concerning videos and images, to be downloaded without a third partie.
Slides is a nice idea, but does not fit very well the actual world where videos and images are nowadays the way people express and transmit an idea. Slides should be autonomous concerning the images and videos. There should not be a third "partie". Something is missing to make Slides attractive.
Thanks for the feedback! Video support is definitely in the plans, there’s already another idea open for it: http://help.slides.com/forums/175819-general/suggestions/5919358-insert-video