This is better than I thought it would be (I read the comments here first). I do agree that some of the content can be glossed over (move some of the internals discussion later in the document), and some figures might be useful -- but you must be careful. I've been fooled by figures more often than I'd like.

Overall I feel like this is a good addition to the Git introduction space.

One big piece of feedback is that would be useful to have a section on obtaining and setting Git up the first time. Especially for Windows users, it may not be obvious.