Haha, same problem here. I always run out of ammo no matter how many bullets I seem to pick up. I end up hustling the zombies or dashing away from them (and getting run over by cars). Gameplay's fine though.
they are really negative in the reviews online about the game :O
but i really love it. i jus started 2nd campaing (Leon) and im really getting the re4 feeling with that ^^