Love that gradient! And the product of course ;)
But I would consider a Call To Action before fold, right under the first hero image. I can almost promise you - it will generate more sign ups :)
I hate to be that guy, but the guidelines for Show HN threads are clear that submissions should actually be ready for use, and not just landing pages like this. It leaves a negative impression when the box marked "Sign up below" is actually just your survey.