1) The accent on the screencast is a bit heavy. No disrespect. But I'd suggest getting a professional voice over.
2) Don't use the word "bottom". Something about the pronunciation made me think of something else. Edit: maybe I am being childish early in the morning. Feel free to ignore this suggestion like all the rest :-p
3) Why are you visualizing such a tiny dataset? I had suspicions this would be slow for a large dataset. E.g. 1K or 1K rows.
4) Why do I have to refresh the page to see new data? Why not a refresh button.
5) Do you not offer functionality to change color, etc. of the visualizations?
6) You don't show how to connect to ones database. A lot of people disable remote access to their DB. Will this work for them?
Some tech question:
1) I liked the drag and drop functionality. What framework are you using?
2) Are you using D3 for visualizations?
Best of luck!