there are a few apps out there that simulate different types of colorblindness that I find useful for testing all sorts of things (websites, apps, videos and more) when I can't easily find someone who is colorblind. you might find them useful for testing, like http://colororacle.cartography.ch/ which looks to be cross-platform (I only know of ones for OS X).
also in terms of general feedback, I love the idea and it's great for occasional use for a small set of pages, but I can't imagine using the current feature set for any significant testing and testing of anything that's not a webpage. i really love the idea of delivering the whole screen, especially without installing much beyond a firefox extension :)
> (im red/green colorblind)
If it is okay with you, can you please email us at dev@colorblind.com so that we can ask you to test few things for us in the future?