I'm looking at the site on an iPad Air. It seems to be working fine, but there are some nuances that could be improved.
It would be nice if the header and the navigation didn't overlap the images. I understand the desire to have the images as large as possible, but I'm not sure it's worth it if it means adding distracting elements on top of the images.
When viewing horizontally, it would be nice if the whole site fit in the screen. It almost does, which means the whole site kind of moves up and down as you swipe image to image. If you could design it so it was responsive and always took exactly 100% of the height you could lock down the vertical scrolling and make it feel more 'solid' and app like.
I would suggest setting a color for your phone links other than the default. On your contact page the phone numbers are quite difficult to read against the grey background.
People generally know how things work if the site is designed well. You probably don't need to add instructions like 'click below for email' or 'Click on links below to view demo reels'