A few hints. 1: there is a map of the area including the gas mask's location, and the ladder. 2: if you look down you can see an "inventory". flares are on the left and rifle rounds are on teh right
The thing i like the most is the sense of satisfaction. For example, when your fighters are outnumbered by a lot but they manage to kill all the bombers, so the city doesn't take damage. 4 out of 5, mainly due to audio bugs( machine gun sounds not playing, the siren not playing sometimes etc)
something i found useful for when i had no pistol bullets: hit the people with the side of your car! they don't grab on when you do that. At least not in my experience.