Concept is awesome
The Instagram this is very cool
The animations are fluid and not OTT like many on here.
You have a few avoidable validation issues (the reviewers are going to get tight on this)
Transitions to about/contact/categories lag a little first time round
I think the nav could stand out more (logo esp gets lost) maybe even consider a full screen over lay or off canvas push menu to make it distinguished?
If it were mine I would lose the images at the top of the about/contact pages just because they draw attention away from the cool side images which are more of a statement
Likewise i’d drop the post copy by a couple of px to around 15px just to tighten it up a bit but generally the typography is very good
Again if it were mine I would do something with the posts esp in category pages to make the text more readable e.g. on hover darken the image to make the post preview text more readable.