Is there a website that compares the features of different cryptocoins?
I think the closest you get is this list of all cryptocoins on Bitcointalk. There is a very brief summery of features there, but you can click further to the corresponding official thread, which should contain all information available on the altcoin.

Sadly, almost none have a thorough explanation of the algorithms involved and are hard to access without looking through the entire code (if available at all). I'm even a bit disappointed in Bitcoin in this case. I have yet to see a javadoc like thorough code documentation for any cryptocoin.