Kimchee is nice, rice with everything (lots of small dishes, very flavourful), dried squid was decent (salty and rubbery - doesn't sound quite so nice when I describe it, but a good snack). I never tried dog. Hot chilli sauce with everything - I couldn't really taste any UK flavours when I came back. Beer was nice, Korean gin is dangerous (especially as a depth charge). Pool bars served yoghurt drinks (yakult-type things before they were a thing over here) rather than beer.
Whether any of that suits I don't know - I went nearly 25 years ago when I was in my early twenties, servings were small, I was doing lots, so the predominance of rice wasn't a problem. I don't really know about immunity - is your concern food poisoning? I never had any problems when I was there and it's a well developed country so hygiene shouldn't be an issue.