This looks fantastic. Watching people's reactions in that example image was really interesting, and it occupied me for a good few minutes. "Why can't you do the same thing with video?" Because rewinding video is really painful, especially online video.

Criticism:

I use my thinkpad's pointer stick to move the mouse cursor. It's impossible to keep the cursor inside the "control strip" while moving it up and down and also looking away from the strip (and at the image). Too much accidental x motion is introduced.

It would be better for me if you were to enable the scroll wheel (which I can simulate on my pointer) as an alternative time control, or perhaps let me click on the control strip and then hold down mouse1 for as long as I want my y motion to control the position in time.