First, the weather was cooler and more breezy when we went. It looks older than Seoul, except some main areas. According to the drama Reply 1997, people in Busan also have a different accent than those from Seoul, which of course Seong could distinguish, but I couldn't! Busan has lots of mountains and hills, so the roads were terrible! We rode a bus and it was not very pleasant.
For our short trip, we took the train and stayed in an AirBnB apartment. We visited the beach, the college area, and the world's largest department store! Here's the video!