Quoting from Quora "The advice we received was that they really like them to be a minute or less because founders/partners only have a few minutes to read each application.

It could be that you gave enough information in that time or that because it was 1:30 they just watched some of it to get an understanding. I wouldn't worry about it though."

http://www.quora.com/Y-Combinator/Our-YC-application-video-f...