Author of the project, amaneureka, is answering questions about it on this HN thread:
I dumped a pile of radical, OS designs on the author to see if any of their better features make it into a future incarnation of it rather than another traditional design. Those are here:
Ignorant question: Is C# virtual machine performant enough to handle an OS? Or is that where the “hobby” portion comes in?
http://joeduffyblog.com/ is an example of C# being used to pretty good effect for OS development. It didn’t see the light of the full user world, but it is quite interesting to read about.