I would change a few things but nothing drastic. All intended to be constructive:
The typography could do with a little work, the main heading starts very close to the edge of the window, it also comes very close to some of the section headings it could do with a little more space. Maybe make it 2 lines instead of one.
The section headings change position some are ranged left some centred, needs to be consistent.
I would keep the menu heading ranged left rather than centred, helps define a strong boundary and just looks cleaner.
I would also make the images align with the heading of the section rather than have them centred to the browser window.
Is it possible to define a set width for portrait and another for landscape images. There's a lot of images that are close to being the same width on screen but are fractionally different. it's visually a bit jarring.
Not keen on the colour change for the contact me screen, theres nothing special about the contacts screen and the colour change give it too much importance.
I would be tempted to have a thumbnail gallery for each section which allows a quickly downloaded overview of the section then the ability to click into the full size images. It's possible that people will be viewing the site on less than ideal connections (smartphone in a gallery) so loading an overview quickly could be useful.
On a technical point you don't need to reload the menu every time a new section is loaded. You can build it so that the menu buttons are a constant.