"Also on the front page: when you enter a URL and hit enter on your keyboard you are taken to some TechCrunch article :)" ... well scratch that, it does not happen any more.
Great job otherwise, I'm "selling" this to my boss tomorrow :)
We've actually just implemented Undo! It didn't make it into the demo video but if you click on the little upside triangle next to a variation's title (e.g. "Variation #1") you have an option to Undo or Redo. There are keyboard shortcuts as well!
As for the front page, is it possible you accidentally hit tab and then enter? If you hit enter right away, it works. If you hit tab, it changes focus to the first testimonial link on the page which is that TC article. We'll fix this so it doesn't happen in the future.
Thanks again for the feedback!