It needs a "Processing..." notification, I clicked "Start conversation" and it takes a while before it says anything. Same with "Start speaking" -> I said something, then clicked "Stop speaking" but the page seemed unresponsive. I repeated it, and when the transcript appeared I ended up answering the question, getting another question, and repeating the first answer.

Also after 3-4 sentences the questions got a bit "dull-person-at-a-party" small-talk... "What are you doing today?" / "I'm programming." / "What programming language are you learning?" / [I didn't say I was learning...] "Java." / "Oh, interesting. Java is a popular programming language. What do you like about Java?".