Okay, I have reached the point in Alien Isolation that I can walk around while hearing the vents echo with the sound of a prowling Alien and feel relatively safe. The only times when I don't feel safe is when said alien decides to hop out of the vents, and when people around me have guns (noise attracts the alien).
Also guns are not your friend in the game, I have used my revolver only once, and that was to deal with an android. They make you reload revolvers in a realistic manner, so only one bullet at a time for revolvers. The only other weapon in the game I have used is the flamethrower, and that was so the alien would run instead of charge (flamethrower is currently my only method of dealing with a charging alien, and it eats through ammo). My total kill count is literally 1 human and 1 android.
Also guns are not your friend in the game, I have used my revolver only once, and that was to deal with an android. They make you reload revolvers in a realistic manner, so only one bullet at a time for revolvers. The only other weapon in the game I have used is the flamethrower, and that was so the alien would run instead of charge (flamethrower is currently my only method of dealing with a charging alien, and it eats through ammo). My total kill count is literally 1 human and 1 android.