One of the best places to find the enemy is underground in the cellar. Then there are embankments and bridges that may be higher than you. If a pesky building is blocking your line of sight there are rules for destroying a building. Artillery and engineers become very useful in the urban environment. I have mentioned several of the results of their activities already.
Artillery can fire smoke, help knock down buildings, or even help isolate an enemy position.
Engineers can blow things up, build prepared positions, block streets, lay mines. and even set booby traps. There are ammunition depletion rules, and even rules for ammunition stores. Another unusual rule involves civil strife. There are a couple of very atypcial scenarios involving a riot by punk rockers, and the Baader-Meinhof gamg trying to escape after a bank robbery. Finally, there are snipers.