Got relatives in Busan... If you ran into them, I hope you said hello.
Now, you probably haven't tried it, but there's a snack usually sold by street vendors, you should try. It's basically sugar, but it's good.
I'm not sure if it's baking power or soda, but a bit is added to sugar and heated until it's melted. After it's melted, it's pressed flat and usually a pattern is pressed into it. I don't know what makes it good, but it's not overly sweet and I love the stuff.
There's another candy much like taffy, but I think it's made from sweet potatoes. I used to love that stuff too.
You might have noticed this, but Chinese food there is different then Chinese food here. If you like spicy, go to a Chinese place and get some Jom Pong (sp). It's a spicy noodle soup with seafood. Another great dish is Ja Jang Mein. I call it Chinese Spaghetti. I call it that because it's a noodle dish with a sauce. The difference is that the noodles are usually hand made and chewy and the sauce is a soy bean based. Those are my Favorite Chinese dishes.... Both are from North East China and very popular in Korea.
For Korean food, go get some Korean BBQ (Kalbi). You've probably already tried it. It's beef ribs marinated in a Soy/garlic marinade then usually cooked at the table.
Regardless of what you try or not try, just enjoy yourself and have fun!!!