OK - on my mobile phone in the un-named browser, when the page first loads I have a large image that is "skewed" (either orientation) with the "Title" verbiage of the gallery and under it the verbiage "View Gallery" - when you hit/touch the "View Gallery" all images disappear including the "Nav-Menu" - an image from the gallery will show briefly when you touch the screen and then it disappears. You can "scroll" left and another image shows but again just briefly then disappears.
On my mobile phone in the Chrome browser it works somewhat but you really have to "fiddle" with it. In "Portrait" orientation you can see an image and "scroll" thru by "swipping" across screen but the "Nav_Menu" that shows doesn't respond when touched. However in the "Landscape" orientation the image covers the "Nav-Menu" when you hit/touch the "View Gallery".
It's very strange cause it all works great in any browser and any viewport (narrow or wide) on my desktop Mac