Wide range of topics covered
The formatting is consistent and nice, barring tha traumatising image (you know the one)
The content can be lacking in some places, but the quality of writing is good
Generally, HTML syntax is correct and valid. As commented one page doesn't close its body tag. Also, some pages may benefit from better indentation to improve readability.
All pages apart from medicine and the index have author details. It is obvious the style has been created collaboratively.