File:Kobani Liberated.jpg

A Kurdish marksman looks over a destroyed area of Kobani, Syria, January 30, 2015 (source)

In a recent interview, IS fighter says the reason they withdrew is that because of constant  airstrikes  no buildings suitable to hide there were left. Judging by this photo, this may be quite (or somewhat) true. Tactics of heavy bombing used here may be unsuitable in bigger heavily populated cities.