It's a nice app and I've been using it for some time, but one thing that's always bothered me is the strange scrolling / caching behavior of the app. A quick scroll down displays a blank page while content is gradually "plugged" in. I don't think I've ever seen this odd scrolling behavior in another app.
It's because stories/comments are loaded on demand. If you never scroll to it it won't be loaded. It was designed this way partly due to how HN API works, which doesn't provide all data up front.
Alternatively app can aggressively load everything up front, which is slow; or paginate content. To me it tends to feel faster when u have progressive UI change (empty card then fill it) than abrupt change (completely empty then all items appear), so I decided not to paginate.