Better yet, add a "guest mode", like https://flowreader.com/ to make having an account optional. (If necessary, limit the number of guests per IP address/range, and the number of feeds per guest).
We could also make a simple "create test account for me", that will give you a few feeds, a dummy email and and dummy password. You can then just change everything later, if you feel like keeping the account. :)
Yeah, this seems to be the biggest complaint in all of this thread. We will do something to make it easier to get an impression of the reader for sure. I don't like screenshots, because, at least for me, the value is in the speed of navigating and the lack of surprises that a single page app will often give you (back button not working properly is the classic).