Nothing happens when running app

[duckpuppy]

With a clean install (just downloaded the release, made it executable, and ran it), I get a blank screen with a cursor. I can press 'h' for the help screen, and I can press 'q' to quit. I can also press 'c' to download my subscriptions OPML... but otherwise, blank screen with a cursor at the left side that I can use 'j' and 'k' to scroll with, but nothing else happens. How does the app retrieve subs?

I tried adding a config.json with the contents from the readme to see if there was an initialization error that wasn't being caught. Is there debugging output I can enable to see what's wrong?