Yea I agree the wording is not ideal. We actually support MOST of the HTML/CSS spec, not a TINY part. Haha.
We're based off a stable Safari/WebKit branch so all of the parsing/handling is same as Safari, but the renderer (eg the shader code) still needs to implement handling for CSS3 drop shadows, CSS3 filters, SVG masks/filters, and few other things.
Also, several platform features are currently disabled (most notably WebAudio and Video, WebWorkers, and few others) and are planning to enable these in a modular fashion in the future.
I'll need to do a proper writeup of what works and what doesn't later but for now you can check out the Browser sample and check it out for yourself.