When you need to be discreet, silenced weapons are your best options. For the others, using a Silencer will eliminate the muzzle flash and greatly reduce the firing noise. This can be especially useful on dark maps where your muzzle flash and noise give your position away. Even on well-lit maps, snipers often use them to conceal their position. Stealth Slippers Stealth Slippers remove your footstep noises.
Most experienced players can hear enemy footsteps approaching, and are alerted.
Wearing Stealth Slippers allows you to sneak up behind enemies and shoot them at close range. For this reason, Stealth Slippers are usually coupled with the Shotgun, Hand Cannon, or Knives. The flashlight can be used in dark areas to illuminate stuff in front of you. Unlike regular Half-Life, there is no 'battery' or other restriction. You can keep it on for as long as you like.