It works great on my 320x480 screen in landscape. The only thing that would make sense would be to limit the viewport width, other than that I don't see anything wrong.
I personally find reading HN on a mobile device really frustrating. Horizontal scrolling is awkward and navigating between comments is frustrating. HN isn't winning any awards for UX.
I really do believe that HN is poorly designed for end users. The UI is not forward with intent, or pleasurable to use. It's been literally years and the expired link issue hasn't been addressed. ---No, I'll stop you right there. It's been acknowledged as an implementation bug, but not addressed. PG's lack of user empathy and stubbornness make HN worse.
It works great on my 320x480 screen in landscape. The only thing that would make sense would be to limit the viewport width, other than that I don't see anything wrong.