I tried it (at http://www.typeform.com/try) and have to say the mix between enter / continue / scrolling and the arrows made it a pretty confusing experience. The partial washout helps a bit though. I wonder how intuitive filling out a form is for the 'non-tech-savy', often an important target audience.

Most advanced form builder evar but their email input isn't input type email for my iPhone to pick email keyboard :/