1. Lots of comments are good, but if you can, process them out before delivery.
2. Line 74: <a> - No href, missing closing tag
3. Line 215: Breadcumbs are typically lists inside of a <nav> tag.
4. Use of alt tags in images are good.
5. Lots of random onchange / onclick attributes. It's better practice and more maintainable to use event listeners.
6. Use of <hr> is okay. Not really needed. Typically represents a thematic break in a passage.
7. No need for self-closing tags in HTML5. They're fine to keep, but optional.
8. Definition list usage is good.
9. Line 173: `active` isn't a good ID name. Should be a class.
10. Line 698: <button> is generally prefered over input type=button, though if you need to support IE6, keep as is.