Thanks for playing! And chapter one was meant to be the feeling of relentless pursuit, so you have to constantly run the moment the sewer locks, as for the flashlight mechanic? If you're able to remember the map well, the clown always knows where your location is, but if you turn your flashlight off he won't run towards you unless he sees you once
Unfortunately this game has been cancelled, however you're still able to play the remains of chapter two! If you have a look at chapter two's design, that was more intended on puzzle and stealth, the flashlight is more useful and the clown follows a determined path all around the house, if he sees you he starts to chase you and will go to your last seen spot :p