This is terrible. It needs step controls for the transport. For example, I didn't see the exact command used to start the 'Nyancat' demo, and the Cap demo is pretty fast-scrolling. If I can't rewind to catch stuff I miss, then it severely compromises the value as a teaching tool. As a matter of fact, lack of proper transport controls is a huge problem for internet video in general. Solve that and you will be covered with gold.
"Seeking" feature is already in development so no worries, you will be able to rewind. Right now you can pause/resume. As for Nyan Cat demo, it was recorded with "asciiio -c 'telnet ....'" command which basically doesn't start shell but immediately runs the command you specified.
Add seeking and ability to do voice-over and this will become an extremely useful tool.