There are a lot of these Kim Bap Chun Guk's in Korea which is to me, an equivalent of a US diner. It is a 24 hour restaurant that is no frills, has all the Korean staples and offers good, cheap eats. We actually ate at this place three times for breakfast during our week in Korea. Due to the time difference, we got up at all wacky hours the first few days and earliest bakery that opened (a Paris Baguette) was 7 AM and we were up well before that.
Thankfully though, the food was decent, cheap, quick, and right around the corner. We couldn't ask for more.
While I am grateful we both can read Korean...it is admittedly, a very, very slow process. Too lazy to spend my entire morning reading the menu, I just read through the "Best Menu" Section selected Buddae Jigae while hubby, being more meticulous, started from the left and settled on the Dduk Ramen.
The food came out piping out in less than 10 minutes and we left happy, full, and with only $8.50 less in our pockets. Though I enjoyed our meal, I learned that eating spicy ramen at 5 AM wasn't a good idea and the following two days, I decided to just go with the kim bap one day (spam = yum) and mandoo guk the following day. My stomach much appreciated it!
These places are a solid, safe bet. As we adjusted to the time difference, we eventually moved our morning meals to a pastry with coffee, but this place saved us for the first three days. Not sure how non-Koreans would feel about eating such heavy food for breakfast, but I guess when you have few options, you will have to learn to love it.