This review is for 3.5 stars.
I was close to a 4 but not quite there. Service was fine but honestly overly in-your-fcae. Might be because there was only one other table occupied so servers were bored and trying to work, but it's a little intrusive when my water is being filled whenever it's 1/3 done and I'm being asked how everything is when a have a mouth full of noodles.
The tonkatsu ramen, extra spicy, had good broth. Pretty spicy and not too much meaty flavor. The chasu was some of the best I've had in town - thick and fatty, almost like pork belly. The noodles were very average and food store quality. The rest of the ramen sides were probably below average, just raw ingredients and boiled egg rather than the good ramen-style egg. My biggest peeve was that the extra spicy addition was $0.75 cents. At that price, I want my face to burn, but it wasn't more than just chili oil.
KoKoRo seems pretty good for a quick ramen or takeout, especially when there's not many options in that area, but not in the top 5 by any means in Vegas.