Fun video to watch at a time I'm trying in vain to do the same. I've been trying to improve my skills in this area, stitching 80~ 100mp with an oly 45 with less than stellar results when done on the quick. In my last round of pano effort I "recorded" around 800 images, spray and pray style, thinking I'd compose later through cropping. It's an insane amount of work. Each tif, output from RAW after applying global edits to exposure groupings inside the set, is around 200 megabytes, and I'm blending up to 50 images at a time in 3 to 4 stacks, then trying to recover some dynamic range in post on the final stitched image. You have to really spend a lot of time making one pano pano layer blended with a priority on exposure and contrast, then another pano layer blended on averaged mean pixels for detail, then merge the two by hand in a photo editor. To get a really nice medium format looking image that preserves all that sweet saturation and micro contrast with insane detail, I think I still need to further decompose the detail pano into 5 or 6 layers with a wavelet tool, then isolate a detail group for each area of the image. If only I had another lifetime to accomplish such a feat, I think I could engineer truly impressive results that would compete with any large format camera. But I'm a mortal. Or you just aim your EM5 or EM1 Mk II, or Pen F at a scene and let the camera do the work in Hi-Res mode.
In the iPhone photo notice that there's no light and shadow on the trees and grass in the right part of the frame. Likewise, all light and shadow difference is gone from the stones. Still, it's fun to play with if you have time for it.