The shoe for the most part is comfortable. They are not a wide width (which I prefer) but stretchy. It fits snug around your foot but it stretches. No loose tongue. It's attached to the material. Even though they are quite comfortable when you first put them on you still need to break them in. The insoles are not bad but would be better with nice inserts. Walking around normally or running in them is fine. Nice shoe for the price. The bubble in the back not sure what it's for. Probably air.