Anyone who has been to Japan have probably eaten at Department stores where there are variety of eateries usually on top floors. They have quite good specialty restaurants these days, but back in the days, I remember seeing something like "okonomi shokudo" where they served all kinds of food in one big restaurant, with all kinds of wax displays that accurately resembled the food they served, which we don't see quite as much anymore.
Koraku reminds me of those "okonomi shokudo"s that are quite out of style in Japan. They serve all kinds of food, from curry to tempura to tonkatsu to ramen, and none of them as well as a specialty restaurant that sticks to one genre of food.
As I went with my family, I got to eat their curry, tonkatsu, and ramen, and I can't say that I was impressed with any of them.
I think this place may have done well 10 years ago, but in these days where they have to compete with Cafe de Japon, Sora, and Monta within a 2 mile radius, they may have a hard time keeping up.
The service was great and the place is comfy with the showa-retro thing going, and I want to like this place, but for me, the quality of the food just didn't do it for me.
I'm still waiting for an authentic tonkatsu place in Vegas....please...someone bring one over.